Donovan nodded and started searching in the pocket of her suit for her phone.

'There were a couple of dirty mugs and some glasses in the dishwasher,' Nina said, starting to walk with him along the corridor. 'Do you want them all printed? They're the only things the cleaner doesn't seem to have scrubbed or polished within an inch of their life.'

'Yes. Anything else?'

'Nothing out of the ordinary so far. You sure you want to look around?'

'You know me. I want to get a sense of her, what her life was like.'

He followed Nina into the living room, where a short, female SOCO was busy dusting the door handle for fingerprints. It was a large room, with three tall windows, stretching almost floor to ceiling, each with a small wrought iron balcony outside. He walked over to one of the windows and stared out at the dark, cloudy sky. It was snowing hard again, dense flurries blowing past the window and adding to the already thick layer on the balcony. No doubt there was still a crowd of hardy reporters on the pavement below, but he couldn't see them. Looking down the hill between the houses, he watched the cars moving slowly in the distance along High Street Kensington, lamps sparkling through the misty air like a chain of fairy lights. He thought of Rachel Tenison as he had first glimpsed her that afternoon in the park, so white and delicate, kneeling down in the snow, like a beautiful flower unfurling.

After a moment, he turned around. The room was sparsely furnished with a mixture of antique and modern pieces. The curtains were neutral, the walls a similar shade and, apart from the back wall which was taken up with floor to ceiling bookshelves, there was no colour anywhere. A large, dark landscape, painted in oils, hung over the mantelpiece in a heavy gilt frame and provided the only decoration. 'Bland' was the word that came to mind. The room looked like an expensive hotel suite, rather than somebody's home. He walked over to the bookcase, which was also plain and functional in style. It was filled with an unremarkable mixture of classics, modern fiction of the type usually found in the bestseller charts, and a smattering of biographies along with a large section on Art History. The only notable thing was the fact that the books were ordered into sections according to category and in alphabetical order. It was how he liked to keep his own books at home, but he rarely came across anyone else of a similar mind.

A collection of silver-framed photographs sat on a table behind one of the sofas, the only items of a personal nature anywhere in the room. Most of the pictures looked at least a decade or so old, judging from the clothes and hairstyles. In one of them he thought he recognised the dead woman, perhaps in her late teens or early twenties, and he was struck by how very pretty she had been, something he hadn't been at all aware of in the park, although death had the effect of reducing everyone to a commonplace waxwork. She was standing beside a tall, serious-looking man with dark hair. He looked older and his arm was wrapped around her almost protectively, while she looked up at him smiling.

'Does she have a partner?' he asked, looking around at Nina, who was standing just behind him.

'Not according to the porter who lives downstairs. He says she lives on her own and I haven't found anyone else's clothing or stuff, so far as I can see. Do you want to take a look at her bedroom?'

'Yes. Maybe it will tell me a bit more about her. I'm getting nothing from this room.'

He followed her back into the hall, where Donovan was still on the phone, and along the corridor to the bedroom at the far end. As he walked in, he saw himself and Nina reflected in a row of mirrored cupboards, which stretched along the entire facing wall. Behind them was a huge, carved-wood fourposter bed, richly hung with curtains of deep red. He turned around, surprised to see something so dramatic in this flat. The bed was made, the linen crisp and white, a pale gold throw draped over the end. Sitting on the floor at the end of the bed was a handsome old-fashioned trunk, covered in weathered black leather and intricately studded with rows of tarnished brass nails. Apart from the bed, it was the only thing out of the ordinary in the whole room and it stuck out like a sore thumb. Wondering what was inside, he bent down to open it, but it was either locked or the lid was jammed shut.

'Haven't come across a key, so far,' Nina said.

'Well, try not to force it open unless you have to,' he said, still looking at it, curious to know why it was kept in such a prominent position and why it was locked. 'It's a lovely thing.'

Apart from a small armchair and a couple of bedside tables and lamps, there was no other furniture in the room. A couple of books sat on one of the bedside tables, along with an alarm clock, but what struck him most was the absence of clothes or shoes, or any of the usual day-to-day clutter and mess of life. He had never seen a room so tidy.

'It's weird,' he said to Nina. 'This place doesn't look lived in, does it? It could almost be a theatre set, although somebody would have made a better job of dressing it.'

Nina nodded. 'We'll bag up the bedclothes and stuff, but according to the note in the kitchen, the sheets went off to the laundry on Friday.'

'That's bad luck,' he said, walking over to a door in the far corner of the room.

He switched on the light and glanced into the small en-suite bathroom. White towels were carefully folded on a rack and the few jars and bottles on show were lined up in a neat row on the limestone counter, with a couple of large bottles of perfume and a dish of soap on the glass shelf above. It was similarly clinical, with none of the usual feminine clutter and paraphernalia. Catching sight of himself in the mirror, he noticed the circles under his eyes and the fact that he had forgotten to shave that morning. Too bad, he thought with a sigh, switching off the light and ducking out again. It was Sunday, after all.

Nina was waiting for him just outside.

'People say I'm obsessive,' he said, 'but this is taking things to an extreme. I've never known a woman's bedroom and bathroom like this. Where's all the stuff you women consider so essential, all the things you can't live without...' He paused, thinking of the armies of bottles, potions and strange, unfamiliar medicines and tonics that had invaded his bathroom from time to time in the past.

'That's a cliche,' Nina said sharply. 'Not every woman's messy.'

'Well, this isn't normal, and it says a lot about Rachel Tenison. What about her clothes?'

'I've only had a quick look so far, but it's all expensive, although quite plain and tasteful, nothing glitzy. As you can imagine, the shelves and drawers are as tidy as a shop display. Everything's colour coordinated, can you believe. We'll go through it all properly once we finish the powdering.'

He exhaled with frustration. He was starting to find the anonymity of the flat and its lack of a human presence disturbing. There was no personality. Nothing. What sort of woman would live like this? He couldn't get a picture of her at all.

He rubbed his chin, gave the room a final cursory glance, and decided it was time to move on. 'You'd better show me the rest of the flat, for what it's worth.'

As they came out of the bedroom, a tall, lanky SOCO padded down the corridor towards them, a large satchel and a camera slung over his shoulder.

'I've almost finished,' he said in a muffled voice to Nina. 'Just got the bedroom to do next.'

'Good. When you're done, can you help Jan with the powdering? Where's Dave?'

'In the study, boxing up the files and the answer machine.'

He squeezed past them and Nina led Tartaglia back down the corridor and into a room at the other end. Apart from a single bed tucked away in a corner by the window, its principal use appeared to be as an office, with a simple modern desk, a chair and a filing cabinet. As they entered, a SOCO shuffled out backwards from under the desk with a long length of cable in his hands.

'What have you got?' Nina asked.

'Nine messages going back to last Friday,' the man said, getting to his feet and pulling the wire free, which he then wrapped around a small answer machine. 'Three hang-ups, four calls from a woman called Selina, wondering where she is, and one from a woman called Liz saying she's running late but will be over shortly. I've listed them with the times.' He passed Tartaglia a sheet of paper from the desk. 'You'll get a full transcript once I get back to the office.'

'Thank you,' Tartaglia said, folding the sheet and tucking it away in his pocket.

He heard what sounded like the flat's front door buzzer in the background.

'I'll go and see who that is,' Nina said.

Leaving the SOCO to unravel the tangle of wires beneath the desk, Tartaglia walked over to the window and looked out. The gaggle of reporters was still on the pavement down below, huddled together in front of the tape. In the distance, he could see the dark tops of the trees in Holland Park. What had she been doing there, he wondered. Or had she been taken there after death?

He turned around, about to go, when he noticed a set of six large, framed, grainy black and white photographs that took up most of the back wall. Each image was of a naked man, wearing a mask. With some the mask covered the entire face, with others just the upper half. The men were muscular, almost overdeveloped, and were posed against a variety of interiors, the images slick, atmospheric, and designed to titillate. Intrigued, he walked up to them and studied them more closely. Each print was signed and numbered in the corner, clearly part of a limited edition, and he wondered how much something like that cost. A small fortune, no doubt. The general feel reminded him of a Herb Ritts postcard of a well-hung man on a motorbike, which a girlfriend had once sent him as a joke. The biker was supposed to be him, although the bike was a Harley instead of a Ducati, not that she knew the difference. While the pictures could hardly be described as hardcore, they were one of the few things possessed of any personality in the otherwise anodyne flat and they made a strange tableau. Even stranger was the fact that they were stuck away behind the door of the study, almost hiding, although if Rachel Tenison had been sitting at her desk with the door closed, she would have been able to enjoy them. It made him think of the Kubrick film Eyes Wide Shut. He was just wondering what it had meant to her and what sort of woman would choose such images, when Nina put her head around the door.

'You'd better come, Mark,' she said. 'There's a lady downstairs. She says she's come to see Rachel Tenison. Says she was supposed to be having dinner with her. She was quite insistent, so they let her through. Sam Donovan's gone down to see her.'

He found the woman sitting at the foot of the thick-carpeted stairs in the lobby. Her head was bowed and she was crying softly. She was wrapped up in a long, black overcoat that enveloped most of her legs and fanned out over the couple of steps above, like a skirt. Her hands were clasped tightly over her face and all he could see was a pale triangle of forehead beneath a mess of long fair hair.

Donovan was sitting beside her, an arm around her shoulders. 'The porter's gone to get her a glass of something strong,' she said, looking up at him. 'Her name's Liz Volpe. She's a good friend of Rachel Tenison's. Apparently they were supposed to be having dinner together tonight.'

'We're going to need to talk to her,' he said quietly, against the sound of muffled sobbing. 'I'll go see if we can use the porter's flat.'

They were soon grouped around the porter's small gas fire in his basement sitting room. The door was shut, the porter no doubt lurking somewhere outside, hoping to catch a thread of what was happening. The cramped space was uncomfortably warm and Tartaglia stood by the window, which he had forced open a few inches to let in some air. Donovan sat next to Liz Volpe on the sofa, a box of tissues between them. A large measure of Bell's had worked its magic and the colour had started to return to Liz Volpe's cheeks.

'She was my closest friend,' she murmured, almost to herself, wiping her face with a hand and shaking her head slowly. 'I just can't believe it.'

It was the first time he heard her speak clearly. Her voice was low and a little husky, as if she had a cold. 'You mentioned that, apart from a stepbrother, she had no immediate family,' Donovan said, and waited for her response. Still apparently lost in her own world, Liz didn't appear to hear.

'We'll need to contact the brother as a priority,' Tartaglia said.

After a moment, Liz nodded. 'Patrick. Patrick Tenison. The MP.' She gulped at the air like a fish out of water.

'Do you have his number?' he asked, recognising the name and stifling a sigh. A body in Holland Park was newsworthy in its own right, but the involvement of an MP in a murder investigation spelled extra, unhelpful media attention. He couldn't picture the man's face, but from what he remembered Tenison held some sort of office in the shadow cabinet.

Liz bent over and fumbled in a large, over-filled black handbag that lay at her feet on the floor. Pieces of paper, keys and various items of make-up and loose change spilled out onto the carpet as she searched. 'My address book...It's in here. Somewhere.' She waved her hand vaguely at the bag and sat back with a heavy sigh, as if the effort was too much for her. Hunched deep into the sofa again, she bowed her head and folded her arms tightly across her chest.

'I'll find it,' Donovan said, gathering up the bag and its contents and starting to rummage through it on her lap.

'Look, I know now isn't a good time, after what you've just learned,' Tartaglia said, wishing he didn't have to trouble her. 'But we're going to have to ask you a couple of questions.' There was no reaction and after a moment he continued: 'Do you have any idea what Miss Tenison might have been doing in Holland Park?'

Again, he wasn't sure if she had heard. He was about to rephrase the question when she nodded slowly again. 'Liked jogging...running...every morning, before work...used to go running together...since we were kids...was going to go this morning...but the snow...decided not to.' Her face was half-hidden behind a curtain of hair and she spoke so softly he could barely hear her and missed some of what she said. But he got the general picture.

'You were supposed to see her for dinner this evening?'

She nodded slowly.

'When did you last speak to her?'

She leaned back and gazed up at the ceiling, as if trying to find the answer. Tears filled her eyes again and she closed them, rubbing her wet face with her hands and finally cupping her hands over her eyes. 'Last week. Thursday, I think. Yes, Thursday.'

'And before that?'

'Not for a while,' she mumbled. 'I've been away.'

'Look, I'll leave you alone now. Sergeant Donovan can see you home, but we'll need to speak to you again, in more depth, first thing tomorrow morning. Please can you give Sergeant Donovan your contact details.' He still wasn't sure that he was getting through. He knelt down so that he was on her level and said, 'In the meantime, I'm sorry to have to ask you this, but can you think of anybody who might have wanted to harm Miss Tenison?'

Her hands slid from her face and she looked up at him shocked, as if he had said something incredible. Against the hot pink of her skin, her eyes were an extraordinary blue.

'Can you think of anyone?' he repeated, when she didn't reply.

'No,' she whispered and hid her face in her hands again.

Straightening, he took a business card out of his pocket and put it on the coffee table in front of her. 'Call me on this number if you think of anything, otherwise I, or one of my team, will see you tomorrow.'

As he walked out of the room and closed the door behind him, his mobile rang. It was Dr Browne at the other end; she had just finished the post mortem. Turning his back on the porter, who was hovering hopefully in the tiny hallway, mug of tea in hand, Tartaglia listened carefully for a moment.

'Right. I'll be over straight away.' He flipped his phone shut and strode out of the flat before the porter had a chance to ask him anything.

3.

He found Dr Browne, still in her gown, stooped over a vending machine in the basement corridor of the mortuary.

'Damn thing keeps giving me white when I want black,' Browne said without looking up, as she punched several buttons impatiently, setting the machine buzzing into action. Tartaglia noticed a number of discarded plastic cups of milky coffee on the table beside it.

Wagner's 'Siegfried' blared out along the corridor from the open door of Browne's office a few paces away. Tartaglia liked opera, particularly Italian opera, but he found Wagner impenetrable, particularly 'Siegfried'. It reminded him of an opera-singer girlfriend who had made him sit through the whole of the Ring cycle before she would go to bed with him. Typical that the music appealed to Browne.

'Damn,' Browne barked, burning her fingers as she struggled to extract an over-full cup from the machine. 'Want a coffee?'

'No thanks.'

Browne took a sip and puckered her lips. 'Don't blame you, it's foul. Wouldn't normally bother with this muck but my filter machine's broken. Let's go into my office.'

She made a sweeping gesture and strode along the corridor, shoes squeaking on the linoleum, with Tartaglia following in her wake. She led him into a small, windowless room, one wall of which was lined with shelves stuffed with medical reference books and papers. The only decoration was a glossy wall calendar hanging over a filing cabinet. February's photograph showed a hearty-looking venison stew with parmesan mashed potato, accompanied by the recipe, and having had little to eat since breakfast, Tartaglia found the sight mouth-watering.

The remains of vinegary-smelling fish and chips lay on a greasy spread of paper on top of a pile of files on the desk. With a grunt that was almost a growl, Browne heaved herself down into a large armchair behind her desk and fumbled in a drawer for the remote, which she used to mute the music. Waving Tartaglia to sit opposite, she stuffed a couple of large, limp chips into her mouth, then gathered up the remains in the paper and dumped the package in the bin.

'As I mentioned on the phone,' she said, giving her mouth and fingers a perfunctory wipe on a crumpled paper napkin before tossing it away, 'cause of death was asphyxiation.'

'Was she strangled?'

Browne leaned back in her chair and started to swivel slowly from side to side, clasping her hands loosely across her stomach. 'The hyoid bone is fractured but there's no superficial pattern of injury, so I would rule out manual strangulation. It could have been caused by a heavy blow, but my guess, based on some other things we found, is that she was held in some sort of a forearm lock.'

'From behind...'

The pathologist nodded. 'There are abrasions under the victim's chin caused by some sort of sharp object.'

'Something on the killer's clothing?'

'Quite possibly.'

'Or a watch or item of jewellery.'

Browne grunted again and compressed her small, pink lips. 'Could be, or something like a metal button or cufflink, perhaps. There are also deep scratch injuries on her face which look like defence wounds.'

'So the killer's behind her,' he said, trying to visualise the scene, 'forearm around her neck in some sort of a control hold. As she struggles to free herself, she scratches her own face.'

'That's about the measure of it.' Browne shrugged, still swivelling. 'We've taken samples from underneath her nails.'

'Let's just hope she scratched whoever it was.' A man was more likely to use an arm lock to subdue a victim, but it didn't take much strength to kill somebody that way; it required only sufficient sustained pressure and the ability to keep holding onto the victim. 'Was she sexually assaulted?'

'Ante-mortem bruising to the thighs and vaginal area would suggest it, certainly, although it's always difficult to be a hundred per cent sure, as you well know. There are also bruises on her neck and breasts and the inside of her thighs consistent with her being bitten or sucked. We've swabbed for saliva but the marks are not clear enough to see a proper dental pattern. What's odd is that all of the bruising occurred at least a couple of hours before death, if not longer.'

He frowned. 'You're sure the interval's as large as that?'

Browne stopped swivelling and folded her arms. 'Most definitely. The bruising is too well-developed.'

'So, the assault and the killing may or may not be linked.'

'It's not clear.'

Tartaglia rubbed his chin, trying to make sense of it. 'But what are the odds of being raped, and then killed, by two different people in the space of a few hours?' he said, almost to himself. 'It must have been the same person or perhaps she wasn't raped.'

Browne shrugged as though it was none of her concern. 'As I said, it's not clear. However, one thing I can tell you is she reeked of booze when I opened her up. The toxicology report will confirm the precise amount but I'd say she was well over the drink drive limit at the time of death.'

'So, she's pissed, has rough sex, consensually or not. Fast forward a couple of hours or so and she's killed and left lying somewhere on her back. Then later, the killer returns and moves the body into the position we found her in.'

'That's about the sum of it.'

'Was she dead when she was tied up?'