'That's right The London boys set it up. It's all Caroline Jackson stuff. A shedload of old e-mails, various business related files and letters. Plenty of stuff to back up my cover story and nothing that shouldn't be there.'

Candle placed his showy aluminium briefcase on the table and snapped open the locks. He produced a flat black rectangle with a cable protruding from one end. "This is an auxiliary hard drive that you can plug straight into your laptop. It's preloaded with all the access codes you need to get into TECS.'

'TECS?' Petra asked.

'The Europol dedicated computer system. It incorporates an analysis system like the one you've trained on, Carol, together with an index system. And we've just got the information system up and running, so you can access all we hold on Radecki and his known associates. Everything Petra and her colleagues have passed on to us is in there, at the touch of a key. There's also an encryption system that will allow you to send secure e-mail to anyone who has the key. Petra, we're also going to make that available to you, so Carol can communicate securely with you via e-mail, which will be much safer than phone calls.

'And to keep it out of sight...' His hand went back into the briefcase and came out with a blue rubber box with a stubby antenna coming out of one corner. 'The coolest radio in town,' he said. 'You can buy them in all the smartest shops. Only, this one's different. The techies stripped out the guts of it and inserted a miniature radio. It works just like the original, but when you open it up -' he pushed a metal slider on the base of the radio and it fell neatly in half - 'there's a hiding place for your spare hard drive.'

Carol and Petra exchanged a look and burst out laughing. 'Boys and their toys,' Carol spluttered.

Gandle looked offended. 'It does work, you know. I Nobody's going to give it a second look.'

'Sorry, Larry, it's very clever,' Carol said, not wanting to alienate her British back-up. 'And you're right, it's entirely unsuspicious.' She reached for the radio and slotted the hard drive into place then closed it up. She pressed a small blue rubber button and static crackled out of the speaker. 'Very good. It's exactly what I need, even if it does make me feel a bit like James Bond.'

'So, that solves your communication problems,' Gandle said, closing his briefcase with a self-satisfied smile.

'Only technically,' Petra said.

'I'm sorry?' Gandle said.

'It's not enough. Undercover is shit. It's the scariest, most isolated place in the world. And then you have the added risk of Zelig's Syndrome.'

'Zelig's Syndrome?' Candle frowned.

'Like in Woody Allen's film, Zelig. Zelig is so insecure that he becomes a human chameleon, taking on not only the style and manner but also the appearance of the people he moves among. It's the big danger for the undercover cop. You spend so much time with these people, alienated from your own culture, that you start to identify with them.'

'You go native,' Carol said.

'Precisely. E-mail is all very well for the exchange of information, but it will not protect you from yourself. For that, we need face-to-face contact.'

Candle looked dubious. 'You already said that Radecki's people are going to be suspicious around Carol. They're going to be watching her. And, with respect, Petra, you're a Berlin cop. Somebody's bound to recognize you. The last thing we want is to take the risk of regular meetings between the pair of you.'

'I think we can do this at no risk to Carol,' Petra said firmly. 'There is a very upscale women's health club a few blocks away from the apartment. As well as the gym and the swimming pool, they have private sauna suites that members can book for half-hour sessions. This is not a place where Krasic or anyone else in Radecki's inner circle can follow us. Trust me, Larry, I would not make an arrangement that would expose Carol.'

Candle looked dubious, but Carol nodded. 'I agree, it's important to keep me connected to the real world. Besides, sometimes you need to talk something through face to face. There might be things that I see or hear but don't understand the significance of, things I might leave out of a written report because I don't realize they're important. But Petra will know the right questions to ask to draw the information out of me. I think she's right, Larry. We need that regular contact.'

Candle fiddled with his silk tie. 'I don't know, Carol. You will be going in and out of Berlin every seven to ten days, we were thinking that you'd get your debriefs then. In London or here.'

'Ten days can be a very long time on the front line,* Petra said. 'It's up to Carol, of course...' She met Carol's eyes, an expectant look on her face.

Carol gave an almost imperceptible nod. 'What you have to remember is that I've never done undercover before. I want all the back-up I can get. If I get burned, I need to be able to get clear in a hurry. With the best will in the world, Larry, you're not going to be much use to me up here in The Hague. If it all goes belly-up, Petra's the one who's going to have to deal with it on the spot. We need an arrangement to cover that eventuality. It's not as if she's going to be sitting glued to her computer twenty-four seven. And if the shit hits the fan, I may not even be able to get back to the apartment to access the computer. I want an insurance policy, Larry, and from where I'm sitting, that's Petra.'

Candle pursed his lips. 'I'm not happy about this. Maybe it would be better if I came to Berlin too. Then you could liaise directly with me.'

Carol shook her head. 'You don't know the background like Petra does, and you certainly don't know the city like she does.' He still looked mutinous. Time to play her ace. 'Morgan told me I should set up systems that I felt comfortable with. And this works for me. If you're still not happy, I suggest we run it past him.'

Candle flushed. 'I don't think that will be necessary. If it's what you want, I'm prepared to support you. Though, for the record, I do have my reservations.'

'Thank you,' Carol said prettily. It was good to know that Morgan's name carried as much clout as she had suspected.

'That's settled, then. Petra, you said you wanted to talk about how I infiltrate Radecki's world. What did you have in mind?'

'If you are going to do these things, they should be done in style. I have a plan that I believe is both stylish and also calculated to hit Radecki in his weakest spot,' Petra said.

Carol grinned. 'I can't wait to hear it.'

The phone was ringing as Tony walked back into his office after a lecture that he feared had bored his students almost as much as it had him. He grabbed it as he slumped into his chair. 'Tony Hill,' he said, covering his ennui with a coating of brightness.

'Dr Hill? This is Penny Burgess. I don't know if you remember me...'

'I remember you,' he said abruptly. Penny Burgess had been the crime correspondent of the Bradfield Sentinel Times when Tony had been working with the local police on his first serial killer case. She'd dogged his footsteps and done her best to turn him into a household name.

'The thing is, Tony, I was hoping we might have a little chat. In the light of what happened in the Court of Appeal this afternoon.'

The danger signs were flashing before his eyes. If Vance's appeal had failed, nobody would care what he thought. 'I'm sorry,' he stalled. 'I haven't heard the news today. What are you talking about?'

'Nobody called you?' Penny sounded surprised.

'I've been teaching. I literally just walked through the door when you rang. What happened in the Court of Appeal?'

'The judges decided that Vance's conviction for the murder of Shaz Bowman was unsafe.'

Tony felt as if a pit had opened at his feet. A spasm of dizziness left him clinging with his free hand to the edge of the desk. Through the buzzing in his ears he could hear Penny Burgess speak. He compelled himself to listen to the words. 'It's not as bad as it seems,' she was saying. 'He was immediately rearrested and charged with the murder of Barbara Fenwick. He's back behind bars, on remand. According to a police source of mine, there was a witness statement from a market trader in the original investigation that completely undermined the case and made the GPS decide not to proceed on that charge back then.'

'I remember,' Tony acknowledged.

'Well, apparently, a BBC radio reporter has been investigating the case, and she's managed to get the witness on tape admitting that he only said what he did because Vance asked him to. He's now completely recanted his earlier statement. So there's going to be another trial, and I hear that the GPS are quietly confident. I wondered what your thoughts on the matter were.'

'I've got no comment to make,' he said wearily.

Tm not asking you to comment on the new charges, obviously that's sub judice. But you must be upset that he's walked free of the murder of someone you were mentoring.'

'Like I said, I've got no comment.' Tony gently replaced the receiver on its cradle. He wanted to slam it down hard enough to break the plastic casing, but the habit of self control was too deeply ingrained for that. He closed his eyes and let out his breath in a long steady stream. That bastard Vance had once threatened to make his life a misery. It looked as though he was fulfilling his promise. He might well be convicted of other killings now, but he had wriggled out of the one murder conviction that really mattered to Tony. Not only that, but the relative anonymity he'd struggled to find had been shattered with a single phone call. Before he could do anything else, the phone rang again. This time, he ignored it. He wondered how long he'd be able to carry on doing that before some bright spark from the university press office decided that what they really needed was the sort of high profile that an interview with Tony Hill(| could bring. He jumped to his feet and made for the door. B Time to go into hiding.

Sometimes there were distinct advantages in having a brother who was a computer expert. Carol had learned enough from Michael to recognize what a program file looked like, which meant she'd been able to identify the encryption software on the secondary hard disk that Candle had given her. It had been the work of a few minutes to transmit the program on to her brother in Manchester, asking him to forward it to Tony, complete with instructions on how to install it. As a result, they were now exchanging e-mails in complete security. Of course, it was all highly irregular - a breach of the Official Secrets Act at the very least. She'd had a moment of doubt, understanding only too well how her apparent cavalier regard for security might be interpreted by someone who didn't know Tony. But it had only been a moment. She knew nobody more committed to confidentiality than Tony, nor anyone who could be more help at the sharp end of a complicated investigation. And Carol had always trusted her maverick streak to do what was best. She had warned Michael on pain of death not to spread the software any further, and she felt sure she could trust him. If it ever came to light, she would plead Morgan's orders that she should do whatever it took to make her feel secure.

This evening, more than ever, she was glad their line of communication was open. For she had something in her possession that might just tempt Tony out of his self-imposed retirement. More than that, it might bring him to her side. Carol frowned at the computer screen. She needed to get this one absolutely right. Impatiently, she pushed the chair back from the desk and paced the room, trying to gather her thoughts.

The apartment in Berlin was everything Petra had promised. Comfortable without attempting opulence, quiet and secure, its anonymity was somehow less impersonal than that of a hotel room. Caroline Jackson would relish those same qualities, she felt sure. The few personal items in the room marked it out as the territory of her alter ego. She'd never have chosen those books, that photograph frame, those extravagantly ostentatious flowers for herself. But for this evening she needed to remind herself that she was Carol Jordan. Caroline Jackson would be no help whatsoever in composing the finely balanced e-mail she needed to send; for that, she needed all her own qualities of mind.

The past few days had been a whirlwind of mental activity. She'd been astonished by how much information Petra Becker had on Tadeusz Radecki, and she could well imagine how frustrated her German contact had become with her team's apparent inability to close down his operations and put him behind bars. He seemed to operate with complete impunity, largely because he had never made the mistake of most criminals, who eventually came to believe in their own invincibility. It was that hubris that brought most of them to disaster, Carol knew from her own experience. But Radecki had never lost the habit of constant caution. His was a recipe for success; he trusted few people, he understood the difference between turning a good profit and greed, and he apparently never breached the firewalls between his deceptively immaculate public persona and the dirty businesses that kept him in style.

The icing on this perfect cake was Krasic, a man who had cultivated a reputation for brutal ruthlessness with apparent glee.

But although Radecki had managed to stay beyond the reach of legal sanction, it hadn't rendered him immune from the relentless probing of Petra Becker. The dossier she had assembled on him was remarkable. Everything from his taste in music to the shops where he bought his clothes was documented. Assimilating this had been Carol's first task, and it brought with it a genuine taste of the undercover life. She had to retain as much of this information as she possibly could while simultaneously shunting it to the back of her mind. Caroline Jackson would know almost nothing of Radecki's life and tastes, and Carol found the necessity of splitting her mind in two profoundly dislocating. That was when she had decided, to hell with protocol, she needed a conduit to Tony.

If she'd had any doubts about the wisdom of her course of action, they vanished in the course of the second evening she spent in the company of Petra Becker. They had used the morning to go over everything Petra knew about Radecki's criminal network, and the afternoon had been devoted to working with Carol's cover story, pushing to see where the cracks might appear, trying to identify possible danger zones and letting her explore the personality she would be living inside for the foreseeable future. Finally, Petra had stubbed out the twentieth cigarette of the day and leaned back in her chair. 'I think it's time to unwind a little,' she said. 'We can't be seen out together once we get back to Berlin, so we should make the most of our anonymity and have dinner out somewhere nice to celebrate the successful completion of phase one.'

Carol stretched her cramped back with a groan. Til drink to that.'

Half an hour later, they were sitting in a quiet booth in a dimly lit Indonesian restaurant. In the centre of the room, brightly illuminated under heat lamps, an extensive rice table buffet was laid out. But for now they were happy to sit with their drinks and unwind. Carol took a healthy swig of her gin and tonic and Petra raised her glass. 'It's been a pleasure working with you these past few days, Carol,' she said. 'I must admit, I had some very negative feelings about this operation, but you've reassured me.'

'Why did you feel so negative about it? Did you think I wouldn't be up to it?'

Toying with the stem of her margarita, Petra studied the liquid as it slid up and down the side of the glass. 'That was part of it. But mostly it was because I felt we'd worked our guts out trying to nail Radecki and it wasn't fair to take it away from us.'

'I can understand that. I'd have felt exactly the same in your shoes. When you spend so long on a case, it feels very personal.'

Petra flicked a considering glance up at Carol. Then, coming to a decision, she leaned her elbows on the table and moved closer. 'Was that how you felt about Jacko Vance? And before that, the Queer Killer in Bradfield?'

Carol's relaxed expression was replaced instantly by wariness. 'You've done your homework,' she said, the distance in her voice shattering the intimacy they'd built in the past two days.

Petra held up her hands, palms out towards Carol, in a placatory gesture. 'Of course I've done my homework. I wouldn't be much of an intelligence officer if I hadn't. But I didn't bring up those cases out of some prurient curiosity. I have a genuine reason for mentioning them.'

Carol wasn't so easily mollified. 'I don't talk about those cases,' she said repressively. Talk about them? I try not to even think about them. I wish I didn't dream about them either. She drank back the rest of her gin and signalled to the waitress for a refill.

'That's cool. I don't want the gory details. I'm not some sensation seeker. But you are the only cop I've ever met who has so much experience in tracking down serial killers. And I need your advice.'

Carol wondered wearily if she would ever leave that part of her past behind her. She had thought she was coming to a place where all anybody would care about was her performance in the here and now. 'Look, Petra, I'm not an expert. The first time, I just happened to be a CID officer in a city where a serial murderer was operating. And the second time was... well, I suppose you'd have to call it a favour to a friend.'

'That would be Dr Tony Hill?' Petra wasn't giving up.

Carol massaged her forehead with thumb and forefinger, shielding her eyes with the rest of her hand. 'That would be Tony Hill, yes,' she said, sounding exasperated. She dropped her hand and gave Petra a cold, defiant stare. It was as if she was challenging the other woman to make something of it.

Petra could sense that her mention of Tony's name had stirred something deep inside Carol, but she had no way of telling whether that was positive or negative. 'I'm sorry, Carol. I don't mean to offend you by asking you about these cases. I realize they must have been tough to work. I really don't mean to bring back bad memories. But if I can explain... ?'

Carol shrugged. She was going to have to work with Petra on the toughest assignment of her career. Already, she liked and respected her and she knew she needed that to continue. It wouldn't hurt to hear what she had to say. 'I'm listening,'

she said as the waitress arrived with her second drink. 'You might want another drink?'

Petra shook her head. 'Later. OK. First thing is, I'm a dyke.'

Carol had wondered, but it wasn't a big enough deal for her to have wondered much. 'Makes no difference to me.'

'I didn't think it would, but that's not why I'm telling you. I'm trying to explain how this all started. I hang out on a private website for gay and lesbian cops in the EU, and that's where I met Marijke. She's a brigadier in the Dutch police, based^n Leiden. We talk three or four times a week in a private chat room, and we've got close over a period of time.' Petra's smile was crooked, self-mocking. 'Yes, I know what they say about meeting people over the net, but it's clear that she is who she says she is, not some impostor fishing for information or a cop junkie who gets off on pretending to be one of us. So, me and Marijke, we each found in the other the sounding board we lacked in our everyday lives.'

'Doesn't make you a sad bastard,' Carol said with a smile of reassurance.

'No. Anyway, Marijke and I have the habit of being confidential with each other. Just over a week ago, she had a murder in Leiden. She told me about it because it was such a strange case, with no obvious suspect or line of inquiry. The dead man, Pieter de Groot, was a professor of psychology at the university there. He was found naked, tied across the top of his desk. The killer had forced some sort of tube into his throat and poured water down it until he drowned.'

Carol shivered. 'That's seriously nasty.'

'There's more. The killer also scalped his victim. But not the head. The pubic hair.'

Carol could feel the hair on the back of her neck bristling erect. She knew enough about psychopaths to recognize the work of a disordered personality when she came up against it. 'Well,' she said, 'it sounds as though it has some of the elements of a sexual homicide. Which means your man has quite possibly killed before and is likely to kill again.'

'Both, I think. When Marijke told me about the case, it rang a distant bell at the back of my mind. And I found the murder of Dr Walter Neumann.' Petra explained briefly what she'd discovered about the Heidelberg case. 'So I began to think that we might be looking at a serial killer operating across national boundaries.' She looked at Carol for a response.

'A reasonable conclusion. From what you've told me, these crimes contain signature elements.' She gave Petra a questioning glance, to see whether she needed to explain herself.

Petra nodded confidently. 'OK, so I figured we had a big problem on our hands. As you know, there's no formal operational liaison between national police forces in the EU, in spite of Europol and Interpol. Oh, we're supposed to swap information and work jointly on transnational crime, and that sometimes works, like with what we're doing against Radecki. But we both know how jealously cops guard their territory. Something as glamorous as a serial killer, nobody is going to want to mount an operation that might take the credit away from them. Getting them to share will be harder than pulling teeth.'

It smacked of cynicism, but Carol knew Petra was right. She also suspected that the greater glory of Petra Becker might be an element in the equation, but that wasn't necessarily a bad thing. She knew herself she tended to be more committed to cases that would make her look good. It wasn't something she was proud of, but she had to acknowledge it as a reality. 'So you decided to sit on it and do some investigating of your own?'

Petra looked slightly uncomfortable. 'I don't know that I'd got as far as making a decision,' she admitted. 'It's true that I wanted to be the one to break the news, and so I asked Marijke to send me the full details of her case. Because, if I was right, he started killing in Germany, which would give us some claim to be the primary investigators.' Petra stopped abruptly and reached for her cigarettes. 'But then, a couple of days ago, there was a third murder. I haven't been able to get much detail yet, but it appears that a Dr Margarethe Schilling from Bremen University has also fallen victim to the same killer.'

'Surely other people are going to pick up on it now?' Carol said.

Petra shrugged. 'Not necessarily. The police forces in the different ladder don't have any formal liaison. There's no central clearing house for information on crimes like murder, only for organized crime. We're a big country and, frankly, most cops are too busy with their own workload to be bothered about what's happening in other cities hundreds of miles away. And it's not like America, where serial killing is almost part of the culture. Here, in Europe, we still don't expect it to happen outside books and movies. No, Carol, the only way anybody's going to make this link is if some detective like me picks up on it. And who's going to connect the murder of a man in Heidelberg and a woman in Bremen, just because they were psychology lecturers?'

'So you're going to have to make it official now,' Carol said.

'Oh, I know,' Petra said, blowing smoke down her nostrils. 'It's awkward, though. The first German case was never directly mine, and if I submit a report to Europol asking them to help co-ordinate an investigation, I will have to explain that Marijke broke her own duty of confidentiality when she told me about the Leiden case. And that is going to drop her right in the shit with her bosses.'

'I see your point,' Carol said thoughtfully. 'Is there any way you could have read about the Leiden case and noticed similarities to the one you'd seen from Heidelberg, then connected those to Bremen?'

Petra shook her head. "There wasn't much detail in the media. Not enough to mark it out as something that would have jogged my memory.'

'I don't suppose Marijke put out a search notice through Europol, to see if there were any other similar cases?'

'I doubt it was even considered. Most cops, especially provincial cops, really don't think of Europol as something that affects them. It's not been up and running in an operational sense long enough to have become part of their automatic thought processes. I would think of it, of course, because my work is intelligence-based. But for someone like Marijke's boss, it wouldn't even cross his mind.'

'Well, if you're serious about wanting to protect Marijke, that might be the way to go. Get her to send a search request to The Hague, on the basis that this case has the hallmarks of the kind of killer who is likely to be a repeat offender and may be operating elsewhere in the EU. That would go out with the regular Europol bulletin, which I presume you see routinely?'

Petra nodded. 'I think my team is one of the few departments that actually reads what comes out of Den Haag,' she said wryly.

'Perfect. Then you can weigh in with your recollection of the Heidelberg case. And bring in the Bremen case as a possibility.'

Petra stared off into the middle distance, examining what Carol had suggested from every possible angle. It would play, she thought. She wouldn't make quite as big a splash as she had hoped, but still, she'd get the credit for picking up on the first known case. And she might even end up as the officer in charge of co-ordinating the inquiry, since it could then be claimed as a German case and nobody would want to leave it in the hands of the woodentops in Heidelberg. But though they might not be overly smart in Heidelberg, they weren't completely stupid. 'There's only one problem,' she said.

'Go on.'

'I asked for the Heidelberg case details to be re-sent to me last week. If there's a new investigation opened up, they're likely to remember that.'

'Bugger,' Carol said. 'You're right, they won't have forgotten that. Look, let's get some food and have a think. Maybe a solution will come to us once we've woken up our taste buds.'

They made their way to the buffet and loaded up their plates with an assortment of starters. For a while, they ate in virtual silence, breaking it only to comment on the quality of the food. Halfway through a chicken satay stick, Petra suddenly beamed. 'I've got it, I think. They sent that case to us originally because they thought it might be connected to organized crime. Now, Radecki's network extends as far as the Rhine and the Neckar. I could say that, in preparation for this operation, I was pulling in everything that might have a possible link to Radecki. I'm notoriously obsessed with this case. Nobody will think twice about me grasping at straws.'

Carol thought it over. It was thin, but it wasn't as if it would have to stand up to detailed scrutiny. Once a serial killer investigation was mooted, nobody would be seriously wondering how the show got on the road in the first place. 'It'll do,' she said. One corner of her mouth lifted in a sardonic smile. 'Somehow, I have the sense that you're not bad at blagging your way past your bosses.'

Petra frowned. 'Blagging? I don't understand this word.'

'Talking your way out of a tight spot.'

'I've had lots of practice. Thank you for your help with this.'

Carol shrugged. 'No big deal. You're welcome. You needed a fresh eye on the situation, that's all.'

Petra pushed her empty plate to one side. 'There's one other thing about this killer that is bothering me.'

Smart woman, Carol thought. In your shoes, I'd be going crazy, not just feeling bothered. She nodded. 'He's not going to stop. You see this slipping away into some no-man's-land of turf wars and arguments over the chain of command. Meanwhile, this bastard is free to carry on killing.' As she saw recognition on Petra's face, Carol realized with a sense of wonder that she was talking like Tony, stepping inside someone else's head and articulating her fears.

'You have put your finger on it precisely. This killer, he is a planner. He is good at what he does, and there is no reason for him to stop until he is caught. Meanwhile, the bureaucrats will be playing their games and the investigators will have their hands tied. It's frustrating.'

'It's more than frustrating. It goes directly against the grain of what your instincts as a cop tell you needs to be done.'

'Exactly. So, in my shoes, what would you do, Carol?'

The million-pound question, with only one possible answer. 'Phone a friend,' she said ironically. Petra frowned. Maybe Who Wants to be a Millionaire hadn't travelled to Germany, Carol thought. 'I wouldn't let it go. I'd do everything I could to progress the investigation myself, and to hell with the official channels. And the first thing I'd do would be to get a profile.'

Petra's face cleared. 'Ah,' she said. 'I see. You would call Dr Hill?'

'He's the best. So yes, I'd call him and try to persuade him to come out of retirement and get back into the game.'

'He has retired?' Petra's disappointment was palpable. 'I didn't think he was so old.'

It dawned on Carol that this whole thing had been one long preamble to try and secure Tony's services for an unofficial serial-killer hunt. Sure, Petra had genuinely needed help with the mechanics of bringing it together in the public domain, but the real agenda was to enlist Carol and Tony on her team. Strangely, she didn't feel at all used. She was genuinely amused, because she identified the strategy as one she would have cheerfully attempted herself. 'He's not old. But he's not profiling any more. After the Vance case, he decided he didn't want to be at the sharp end any longer.'

Petra looked dismayed. 'Shit,' she said. 'I thought maybe ...' She shook her head, clearly angry with herself.

'You thought exactly what I'd have thought in your shoes,' Carol said gently. She felt for Petra, knowing how discouraged she would have been in the same position. On the spur of the moment, she made a decision. 'Look, leave this with me. I saw Tony only a few days ago, and I've a feeling he just might take the bait. He's not enjoying the quiet life as much as he'd hoped. This could intrigue him enough to draw him back into combat. Meanwhile^ get Marijke to set the official ball rolling. The sooner the better. And I'll do what I can to help.'

'I think you have enough to be worried about without this,' Petra said, halfhearted.

'It'll give me something to keep me grounded in who I really am,' Carol said. 'Nothing like reality to beat Zelig's Syndrome.'

So now she had to keep her promise to Petra. She had to find the words that would entice Tony to give his help. She had the feeling she was kicking at a half-open door, but it would still take all her powers of persuasion. Carol walked through to the kitchenette and opened a bottle of red wine. Time for a little Dutch courage. First, she had to e-mail Tony. Then she had to prepare for tomorrow, when she would finally come face to face with Tadeusz Radecki.

Tony stretched his arms out, feeling the crack of joints in his neck and shoulders. He was getting too old to spend the evening hunched over a computer screen. But it was as good a way as any to escape from the complicated reaction the news about Vance had provoked in him. He'd unplugged the phone and immersed himself in work, avoiding thought and journalists alike.

He closed down the file he'd been reading, the draft dissertation of one of his graduate students. It wasn't a bad piece of work, although the theories ran ahead of the evidence in a couple of crucial places. He'd have to take a stern line with her in their next supervision session. She needed to iron out these problems now, before they became too entrenched to unpick easily.

Before he switched off, he crossed to his communications program and flicked the button to send and receive all mail. It was always worth a late-night mailbox check; he might be heading for bed, but much of America was still in the middle of the working day, and he was in regular touch with several friends and colleagues on the other side of the Atlantic.

Tonight, there was a single message. He activated the encryption software that Carol's brother had sent him and opened her email.

Hi, Tony,

Well, here I am in Berlin. There's a real buzz here, it feels like a place that's doing well for itself. Which, as we know, is always a good breeding ground for the more sophisticated sorts of crime!

I've not made contact with TR yet - that's scheduled for tomorrow night, when we see if Petra's strategy will work or explode in our faces. I know you said you thought it was psychologically sound, but I'm still feeling very nervous about it. Now that it's so imminent, I'm a basket case. I can't eat and I know I'm going to struggle to sleep tonight. I'm having a few glasses of wine to take the edge off, but I'm not convinced that'll make any difference. Petra has been working me intensively, and I suppose that should give me some confidence. I can't say that it has, however. Although I feel I know TR pretty well, I'm not sure I know who Caroline Jackson is ... Let's hope I don't fall flat on my face at the first hurdle.

Anyway, talking about this is only making me more nervous. And the real reason I'm writing to you tonight is actually nothing to do with my undercover.

When we saw each other recently, you seemed to be suggesting that you would welcome the chance to use your skills in criminal profiling again, if the right opportunity came along. Well, I think I might have the very thing for you.

The basic scenario: definitely two, possibly three murders that we know of. Two males, one female. All the victims have been psychologists working as university academics. They have all been found lying on their backs, bound hand and foot to their desks. Their clothes have been cut away, leaving them naked. The cause of death was drowning - they had a tube forced into their throats and water was poured down it until they died. And there is an interesting postmortem mutilation: the killer scalped their pubic area. No damage to the genitals, just the removal of hair and skin.

The problem: the first murder that we know of took place in Heidelberg in Germany, the second in Leiden in Holland, the third (the possible) in Germany again, in Bremen. The connection was made because by chance Petra had seen details of the first case, and a friend of hers, Marijke, who is a cop in Holland, told her about the second case and Petra spotted the link. Then, when the third murder of a psychology lecturer was reported, it jumped out at her, even though she hasn't got enough detail yet to be certain it fits. So, as you will see, there is a jurisdictional nightmare ahead. What's more, ifs not formally out there yet because we've had to work out a way of officially linking the cases without dropping Marijke in the shit for talking out of school. Some time over the next few days, though, ifs going to be shunted through Europol, which should start the wheels moving.

But I don't have to tell you how it will get bogged down in the machinery of bureaucracy. Petra thinks it's unlikely that anyone else has made these connections yet, given how little communication there is between German police forces on the ground (sound familiar???). Petra also thinks, and I agree with her, that he's going to take more victims before a properly constituted international task force can get moving. So she wants to try to short circuit that process with an unofficial investigation.

To a large extent they're working in the dark. This killer seems to be very good at covering his tracks. There seems to be almost nothing from forensics in either case.

Why has Petra taken the risk of spilling the beans to me? Well, let's not forget that she's in intelligence. And she'd done her homework on me. Which led her inexorably to you.

Obviously, what the girls want - no, what they NEED - is a profile. And, like the song says, nobody does it better.

And Petra wants the best.

It's a chance to get back into the game, Tony. And it would be a safe environment to do it in. Because it would be entirely unofficial, you'd be working out of the public eye, nobody looking over your shoulder expecting instant results. No stories in the press pressurizing you to come up with the goods. Simply a low key piece of work that might just save some lives.

Of course, if the girls do manage to pull something off, you'd get the credit, which would maybe open some doors for you in Europe.

Please don't feel you have to say yes on my account. I've told Petra that I don't hold out great hopes. But I'd like you to say yes on your own account, because I don't think what you're doing right now is giving you much sense of satisfaction. And doing what you do best might make you feel happier with yourself.

Think about it. Take care,

Tony scrolled back to the top of the message and reread it more slowly, the occasional ironic smile twitching the corners of his mouth. She was good, he had to admit. She'd always been quick, and she'd learned a few neat little tricks along the way. He wondered how long it had taken her to compose something so apparently artless but which was nevertheless clearly calculated to push all his buttons. There was enough information about the cases to whet his appetite, but not enough to allow him to draw the conclusion that they lacked sufficient interest to suck him in.

Oh, and it was very cleverly done. Right down to bait that it would be a black exercise, off the official books, something entirely deniable whether it went right or wrong. 'And it would be a safe environment to do it in.' The subtext being, of course, that there would be nobody to see the egg on his face if his skills had gone rusty and he fucked up. He didn't think Carol believed that would happen, but he understood that she thought he might carry that fear. And she was right, too.

It was tempting. But he wasn't sure if he was drawn to it for the right reasons. The thought that kept butting its way to the front of his mind was that it would provide him with a legitimate excuse for getting on a plane to Berlin, because naturally he'd have to consult in detail with Petra, who seemed to be in the driving seat of this black operation. And Berlin right now meant Carol. Carol, who could benefit from the support he could offer. Carol, who had never been out of his thoughts since he'd left London.

And that was a dishonest reason for snatching this opportunity. If he went to Berlin for Carol's sake, his mind wouldn't be focused on the job he was supposedly there to do. Worse yet, his presence might prove to be the opposite of helpful for Carol. She needed to stay in role as much as possible, and if he kept popping up like a jack-in-the-box, it could damage her ability to maintain Caroline Jackson. Providing insights and reinforcement from a distance was one thing; to be there in person could tempt her to lean too heavily on him. Then if it came to the crunch and she was thrown entirely on her own resources, she might lack the necessary confidence to carry it through.

Still, he thought, it wouldn't hurt to check it out on the web. He loaded his search engine and typed in, 'Bremen + murder + psychology + lecturer', going for the most recent one first. Seconds later, he was looking at a German newspaper report. Luckily, he'd learned German at school and had kept it up so he could read scientific papers. But even if he hadn't been able to understand it, one thing would have leapt out like a firework in the night sky.

Tony stared at the screen, scarcely able to believe his eyes. There had to be a mistake. His hands clenched into fists and his face closed in a frown. He rubbed his temples with his knuckles, trying to make sense of what he was reading.

There was, however, no room for doubt. There couldn't be two Margarethe Schillings who were psychologists attached to Bremen University. That was beyond the bounds of credibility. But equally impossible was the idea that Margarethe Schilling was dead at the hands of a serial killer.

He could see her face now. Wide mouth grinning at something someone had said, laughter lines scored in the corners of her eyes. Hard to believe any psychologist could have found enough in the world to laugh at to etch them so deep. Blonde hair loose, impatiently pushed back behind her ears when she was making a point in debate. Lively, intelligent, argumentative to the point of being infuriating.

They had met at a symposium in Hamburg three years before. Tony had been interested in the relationship between religious belief and certain types of serial offender, and Margarethe's experimental work had intrigued him. He'd listened to her paper and found several points he wanted to discuss with her. So they'd gone off to a bar with a few others and missed the official banquet, so wrapped up had they been in their discussion.

They'd found a lot of common ground, him and Margarethe. So much so that she'd persuaded him to change his flight and come back to Bremen with her for a couple of days so he could see her research results at first hand. It had been a fascinating experience, and the vigorous exchange of information and ideas had exhilarated him. She'd even put him up in the spare room of the charming nineteenth-century barn conversion she shared with her husband Kurt and their son Hartmut in a small village near an artists' colony a dozen miles from the city.

He hadn't taken to Kurt, he recalled. He'd made not a virtue but a martyrdom of necessity, complaining about his boring life of childcare following his redundancy from a research post with a pharmaceutical company. 'Of course, having to look after a child all day means it's impossible for me to keep my knowledge current,' he'd moaned over dinner. 'It's all right for Margarethe, she can scale the heights of the academic world, but I'm stuck out here in the backwoods with my brain rotting.'

It had become clear to Tony that Kurt was parenting not out of necessity but out of idleness. According to Margarethe, his parents had left them enough money to buy the house with a little left over. Kurt had seized the chance to take redundancy with the intention of assuming the life of a dilettante. As she told the tale, Margarethe had smiled wickedly. 'The first thing I did when he told me what he'd done was to sack the nanny. He couldn't argue with me, because it would be like saying he didn't want to spend time with his son. But he's never forgiven me for it.'

At the time, Tony had thought it was remarkably bad psychology for someone who made her living out of the labyrinth of the human mind. Unless, of course, she had wanted the marriage to fail. Which had followed with depressing inevitability, as he'd gathered from her Christmas cards and occasional e-mails. What she hadn't expected was for Kurt to hang on to Hartmut, and he could tell, reading between the lines, that the loss of her son had devastated Margarethe.