'I remember a journalist, some chap she was at university with. He came into the gallery a few times recently I think he was doing a piece about Nazi looted art but there was nobody important that I was aware of, nobody who would feel strongly enough to-'

'It's impossible to tell, Mr Greville, what people feel, what they show, what they keep hidden. I'll need all the names you can think of.'

Greville sighed, as if it was all an enormous effort. 'The chap at Christie's...he was called Rupert something...in British Pictures, I seem to remember. Maybe he's still there. The journalist's name was Jonathan, but you'd better ask Selina. She knows more about this sort of thing and she's mistress of the diary.'

'And what about you, Mr Greville?' She held his gaze. 'I understand you had a relationship with Miss Tenison.'

He stared at her, pursing his thin, dry lips and sucking in his breath sharply. 'I really don't think that's any of your business.'

'Everything is our business. Please can you tell me about it.'

He knotted his hands and looked away. 'There's nothing much to tell, really.'

'But it went on for several years, I understand.'

'Yes. But it was over many moons ago and, as I said, it's really none of your business.'

He spoke dismissively, as though what had happened was something unimportant, but his eyes were watering and his face was flushed. He refused to look at her.

'I'm sorry, Mr Greville, but I really do need to know more. Did she end it or did you?'

He felt in his trouser pocket and pulled out a large, creased blue-checked cotton handkerchief and blew his nose loudly. 'She was the one who ended it,' he said, stuffing the handkerchief forcefully back in the pocket with a sniff.

'Were you unhappy about it?'

He shook his head, bewildered. 'It didn't make sense. There was nobody else, you see, nobody else.'

'You're sure?' she asked, wondering if Greville was being naive.

'Yes,' he said, looking affronted. 'There was no reason for it. I gave her what she wanted. She was safe with me.'

It was such an odd remark, Donovan lost her train of thought for a moment. 'What do you mean by safe? Safe from what?'

Greville sighed deeply and gazed into the distance. 'What I meant was, some people like danger, like to put themselves in the way of temptation and trouble. I was a safe haven for Rachel, what she needed.'

'You're saying Miss Tenison liked danger?'

'I'm saying she needed looking after. She was fragile. A delicate creature. Like a precious, beautiful flower. I took care of her.' A brief smile of affection illuminated the sadness of his pale, worn features.

'Like a father figure?'

Greville knitted his brow as though he didn't like the word. 'I suppose I could give you all the obvious kitchen psychology crap about her background, but it's not really relevant, is it? My lovely, lovely girl is dead.'

Holding Donovan's eye almost challengingly, he reached behind him and fumbled until he found the catch to the cupboard. He yanked it open and retrieved a bottle of Famous Grouse. It was about a third full and he poured a good inch or so into his glass.

'Did your wife know about your relationship?'

'No, she did not,' he said firmly, struggling to screw the cap back on as though his fingers were stiff and putting the bottle down on the desk in front of him. 'And I want it to stay that way, do you hear?' He sank back into the chair and took a gulp of whisky.

'If you've told us the truth, Mr Greville, and your wife does the same, and your alibis check out, there's no reason for her to know anything about what went on between you and Rachel Tenison.'

An expression of relief passed over his face and he smacked his lips. 'Good. As I said, it was all in the past. There's no point upsetting her now.'

'It would be helpful if you could give us a DNA and fingerprint sample so that we can eliminate you from anything found in Miss Tenison's flat.'

'Fine by me.' He gave a vague wave of his hand.

'We'll also need to check where you were on Friday.'

'Be my guest. I've nothing to hide. Speak to BA. They'll confirm that I was on the first flight out to Geneva on Friday, crack of bloody dawn.'

'Thank you. We shall.' Feeling that she had probably got as much as was useful out of Greville for the moment, Donovan stood up and took a card out of her bag, which she pushed across the desk. 'If anything springs to mind, however trivial, please give me a call.'

He nodded. 'Of course. Liaise with Selina about the files and Rachel's diary, will you? Whatever access you need is fine, but speak to her. She deals with all the admin crap.'

Donovan walked out of his office, half closing the door behind her. As she turned to go up the stairs, she caught sight of Greville's long, pale face framed in the narrow gap. For a moment, he stared down at the desk in front of him, as if lost in thought, then he bowed his head and put his face in his hands. His shoulders started to heave and it looked as though he was crying, although there was no audible sound. From what she could tell, he had told the truth and her heart went out to him.

Upstairs she found Minderedes perched on the corner of Selina's desk.

'Time to go,' she said briskly. 'Got everything we need?'

'Yes.' Minderedes slid off the desk and started to walk with her towards the door. They were almost out in the street when he looked back at Selina, made the shape of a phone around his ear and mouthed the words 'call me'. Donovan said nothing and went out into the street ahead of him, letting the glass door slam behind her. If he wanted to behave like an idiot, it was his lookout.

It was freezing cold, the sky threatening again, and she pulled her coat even more tightly around herself. There was still some snow on the ground but it was turning into slush and her feet felt wet even after the short walk from the car to the gallery.

'Don't know about you,' she said sharply, as Minderedes emerged through the door, grinning, 'but I need a coffee and something to eat. There's still time on the meter, if we're quick.'

'Yeah. Could murder something hot.'

They crossed the road to a small cafe on the opposite side and bought pastries and coffee, taking them to the counter in the window where they stood looking out at the street and the Greville Tenison gallery. Even though it was nearly lunchtime, there were few passers-by and hardly any traffic, most people kept away or inside because of the cold. Within minutes she saw Richard Greville come out, dressed in a long dark coat and brown hat. He walked away along the road and turned down Hay Hill towards Berkeley Square.

'Greville was on a six-fifty flight to Geneva last Friday morning,' Minderedes said, in between bites of a large cinnamon Danish, a second still waiting untouched on his plate. 'The flight landed about nine-thirty local time, then he had meetings with a couple of clients which took up most of the day. He spent the weekend with some other clients near Basle.'

'What about Mrs Greville?'

'She apparently stayed in London. I've got the home address and I'll go round and see her later.' He crammed in another mouthful of pastry. Elbow on the counter, beige mac carefully folded over his arm, he picked at any fallen scraps of pastry or nuts as if it pained him to see anything go to waste. How he remained so skinny was a mystery.

Donovan took a small bite of her croissant, wishing that she didn't feel quite so hungry. 'You'll double check with the airline to make sure he actually took it?'

'Of course. But if so, he's out of the frame.' Minderedes raised his thick brows and grinned at his attempt at a pun, brushing away a light dusting of icing sugar that had fallen on his tie.

'What about Selina? Does she have an alibi?'

'At home. Her flatmate can corroborate. You really think the killer could be a woman?'

Donovan took a gulp of the unpleasantly milky cappuccino. 'Can't rule it out, although as we all know, it takes a lot of strength to shift a body. I just don't see a woman using an arm lock unless she's been in the armed forces or had some sort of martial arts training. What about the missing laptop and phone?'

'Still missing. Apparently, she kept the laptop at home and rarely used it for work. I've got a note of her personal email address, although any emails she's already downloaded onto the laptop won't be kept by the service provider. At least her work computer's backed up on the office network. As far as Selina knows, her BlackBerry was her only mobile phone, but it only links in to the work email.'

'So, it looks as though they've been taken. What about her diary? Is that on the network?'

Minderedes nodded. 'I've got a printout and Selina's emailing the full version along with the client list. Most of the clients live overseas, so hopefully it will be pretty easy to eliminate them.'

'How about the American she was due to see on Friday?'

'He's still in town. I'll go over to his hotel once we're done. Selina says it's only a couple of minutes walk from here.'

'So what did Selina have to say about Greville?' she said pointedly.

Minderedes used a paper napkin to wipe a trace of milky foam from his lips, folding it carefully and putting it down by his plate. 'She's only been there a couple of months but she said he and Rachel Tenison got on like the proverbial house on fire.'

'We'll need to speak to whoever worked there before.'

'All under control,' he said, patting his breast pocket with a tight smile. 'I've got the woman's name and the phone number of the agency. Anyway, according to Selina, the gallery's doing really well. I'll check with the bookkeeper and the accountant, and the bank of course, but it all sounds hunky-dory. Not a whiff of anything smelly there.'

'What about Rachel Tenison's private life?'

'According to Selina, she didn't have much of one or, at least, if she had anything personal going on she didn't shout about it at work or scribble it all over her diary. Her work's her life, you know the line.'

'What about Thursday?'

After biting the corner off his second pastry, Minderedes took a folded sheaf of papers out of his pocket and leafed through until he found the right page. 'Thursday, here we are. Not a lot going on, apparently. They were getting stock ready for Maastricht.'

'Maastricht?'

'It's some sort of big art fair in Holland. Anyway, the carrier delivered some canvases back from the framers in the afternoon and Rachel Tenison cut out around six, after they'd gone. Said she was meeting someone for a drink.'

'Who?'

'In the diary it's down as "JB drink".' He showed her the page, then folded the papers away in his pocket. 'Doesn't even say where they were meeting. Selina said that sort of shorthand entry was normal, even for business contacts. Said she got to know who most of them were if it was to do with work, but JB doesn't ring a bell.'

'So, it's personal. What a way to run an office.'

'Selina said Greville's even worse; it's impossible to keep track of him. He can't work a computer and keeps a written diary in his pocket, which she has to take off him from time to time to enter into the system so she knows what's going on.'

'Sounds very stone age, but I suppose if it's just the two of them they can just about make it work. What about the phone records?'

'Copies are on their way.'

'So, what else did Selina have to say? You two seemed to be getting on really well, from what I could see.'

Minderedes gave her another smile. 'Nice little girl, Selina. Very helpful. But not really my type.'

'You don't have a type,' she said, with a derisory snort.

Minderedes shrugged. 'Whatever. She'll have the files ready if we want them but she says she can't believe any of the clients would kill Rachel Tenison.'

Donovan put down her cup and studied him for a moment. Slick Nick. That was his nickname around the office and he seemed quite pleased with it. It certainly summed him up, with his bleached teeth, sun-bed tan and fine gold chain around the neck, but he was nothing more than a well-seasoned alley cat and it amazed her how many women were taken in. She supposed it was all a matter of confidence, in his blood from birth. Not for the first time, she found herself wishing that life would deal him a few hard knocks; anything to bring him down a peg or two, although people like him always seemed to be Teflon-coated. She envied him his lack of self-doubt. How easy life must be if you always thought you were right.

'You're going to take her out, aren't you?' she asked. Although he didn't reply, she noted the stubborn tensing of his mouth as he drained his coffee. 'Don't bother to lie.' She just wanted to hear him say it, watching the colour rise to his sallow cheeks as he avoided her eye. 'Can't you play it straight, for once? Can't you interview a woman without trying to get into her knickers?'

He slammed down his cup, making the spoon jingle in the saucer, and glared at her. 'What's it to do with you? I'm allowed a life, aren't I?'

'If it's female and it moves, shag it. That's your motto.'

'For fuck's sake, she's over sixteen. She can make up her own mind. Anyway, with the hours we work, how the hell am I supposed to meet anyone who isn't a sodding, pain in the arse, uptight policewoman? Tell me that.'

'You seem to manage pretty well, from what I've seen. You know what Mark will say, if he finds out, don't you?'

At the mention of Tartaglia's name, Minderedes bridled. 'Going to tell him, are you? Whisper in his little ear, all cosy cosy, just the two of you? That's what you'd really like, isn't it?'

'That's a load of crap and you know it,' she said vehemently, wanting to slap his face.

'Anyway, what about him and that red-haired pathologist? Fiona...what's her name? She cuts up the bodies and he gets his end away. Very nice.'

'Christ, you're twisted. Anyway, that's history, not that it's any of your business.'

'Nor is it any of his fucking business what I get up to in my own time.'

'Yes it is, if it's to do with an ongoing case.'

'Selina's not a material witness, right? And you're a fine one to talk. What about you and-' He stopped short, mouth half-open and stared at her horrified for a second, before clamping his mouth shut and fixing his gaze out the window as if there was something very interesting to see on the other side of the road. His embarrassment was the only thing that stopped her from punching him.

He was referring to the man known as Tom, a serial killer who had murdered several young girls, who had put both her and Tartgalia's lives in jeopardy. Nobody at work dared mention to her face what had happened. But she knew they all talked about it behind her back, hushing their voices sometimes, cutting conversations short when she came into the room. Christ, how naive they were, especially for a bunch of detectives. Did they really imagine she had no idea what they were talking about? But there was no point in having it out with Minderedes. He wasn't worth the breath. Anyway, he was just echoing what they all thought. The best thing was to try and ignore it, not give him the satisfaction of a reaction.

Suddenly, she became aware that the cafe had become very quiet. She turned around to see several faces looking at her. Wondering how much they had overheard, she scooped up her bag and turned to Minderedes.

'I'm going to try and trace the poem,' she said in as flat and business-like a tone as she could muster. 'Call me when you've spoken to the client.'

Without giving him the chance to say anything, she strode out of the cafe into the cold street.

7.

It was late afternoon and already dark when Wightman dropped Tartaglia in front of La Girolle, a restaurant in the backwaters of Kensington, and sped off around the corner in search of a parking place. Rachel Tenison's name and photograph had been released to the press earlier that morning, with an appeal for help in tracing her final movements, and calls had started to come in with possible sightings and information. One in particular sounded interesting. The manager of La Girolle had called in to say that Rachel Tenison had dined there with an unknown man on Thursday evening, the night before she was murdered, and as the location was close to where she had lived Tartaglia decided to follow it up himself.

Waiting for Wightman, he took shelter from the cold wind underneath the restaurant's wide, black awning, admiring the huge lead tubs of designer topiary that were chained and padlocked to the railings to prevent theft. A few minutes later, Wightman came thudding down the pavement, just as Tartaglia heard the sound of his phone. 'Go and find the manager,' he said to Wightman, flipping open the phone. 'I'll join you in a minute.'

It was the CSM, Nina Turner. 'We're done here now,' she said, 'but you told me to call if I found anything interesting in the flat.'

'Spit it out.' He was freezing cold and impatient to cut to the chase.