Ghita answered the door immediately, as if she'd watched Kathy's approach from behind the net curtains.

'How are you, dear?' She offered Kathy a cheek. Both she and her husband had the coal-dark eyes that Kathy found so disconcertingly attractive in Leon, but in their sagging faces the eyes gave an impression of deep fatigue, as if recovering from a very long period of watchfulness. Ghita peered at Kathy now through those dark eyes like someone conducting a physical.

'Are you sure everything's all right? There is nothing wrong?'

It was the unexpected visit, the rarity of direct contact, and suddenly Kathy realised that Ghita a.s.sumed she had come to deliver some momentous message concerning herself. 'Leon and I have decided to get married', perhaps, or more likely, 'You're going to become grandparents'. Yes, that was it. Ghita thought she was pregnant and had come alone to spill the awful beans. Because Kathy also saw, from the sombre expression on Ghita's face, the way she held herself braced, that such news would not be welcome. Not from her.

'No, everything's fine. Absolutely. How is Morarji?'

The brow between Ghita's dark eye sockets creased in a tiny frown of doubt, then eased. 'He's much better, really.

But he gets tired. He's just having a little nap. You don't mind, do you?'

'Of course not,' Kathy said, wondering if he'd been packed off so that Ghita could have this out with her alone, woman to woman, without any fudging from Morarji, who liked her. 'These are for you.' She handed over the flowers and followed Ghita through to the living room. There was a smell of baking and air-freshener.

'Sit down, dear, while I put them in water and pop the kettle on.'

Kathy had never been left alone in this room before.

Ghita was an immaculate housewife and every surface gleamed. She noticed a small perfume dispenser plugged into an electrical socket. There were embroidered linen protectors on the arms and backs of the brocade suite. On the mantelpiece were mementos of their days in East Africa, from where they'd been expelled, and above them a rank of framed family photographs, Leon conspicuous.

'And how is Leon?' Ghita bustled back in.

'He's fine. He's taken quite an interest in cooking lately.

He's getting really very good at it.'

'Cooking?' Ghita looked appalled for a moment, until she managed to smooth the expression away. 'Well, I'm sure that will come in handy. And his work?'

'He's working too hard.'

'Ah,' Ghita shook her head. 'That job.'

'The trouble is he's so good at it. He's in demand.'

'He would be good at whatever he set his mind to. It's a mistake.'

'You mean forensic liaison?'

'I mean the police!' she said with sudden pa.s.sion. 'It was always wrong for Leon, always.'

Kathy hadn't realised the depth of Ghita's opposition to Leon's work, and as she went on about the pay and hours, the dreadful experiences, and compared them to what a cousin of his in IT was getting in the City, Kathy thought of Charles Verge's mother, equally dedicated to her only son. Both mothers had brought them up in some isolation, Madelaine as a widow, Ghita as a refugee, which had probably lent a certain intensity to their relationships with their sons.

'That was why I told him to go for the Liverpool course, as a way out, into the private sector.'

So Ghita had encouraged that, which Kathy hadn't realised. She felt as if she were seeing his mother for the first time, as if all their previous encounters had been so wrapped up in courtesies that nothing at all had been communicated.

Ghita obviously sensed she was getting onto dangerous ground, and moved onto a neutral topic. Were they planning a holiday this year? Time went so fast, the year was nearly over, and they hadn't managed to get away. When Morarji felt a little stronger they might try to have a break, somewhere warm . . .

She was interrupted by a movement at the door and the voice of her husband. 'Talking about me?' Naturally short and plump like his wife, Morarji Desai had lost weight, Kathy saw, and the dressing gown seemed to swamp him.

But the good humour was as bright in his eyes as ever as he advanced across the room to kiss Kathy's cheek, ignoring Ghita who was immediately on her feet and objecting to his being out of bed.

'Ghita worries too much,' he said with a wink.

'Well, somebody has to,' she snapped back.

'It's a division of labour, you see, Kathy. She does all the worrying and I do all the fooling around. Very efficient.

We're both experts in our own fields.'

It was true, and when Kathy tried to place Leon between these two poles she had to conclude that he was closer to the mother's. Morarji sat down with a chuckle while his wife went to fetch the tea. 'She wasn't giving you a hard time, was she?' he asked, voice lowered.

'No, no. We were just talking about Leon.'

'Of course, what else? But how about you? He tells us you're working on the Verge mystery now. What an exciting life you lead, eh? I have my own theories on what happened, you know . . .'

But Morarji never had the chance to expound them, for his wife returned with the tea and abruptly changed the subject. 'Leon told me to ask you to please pick up his computer and take it back with you.'

The computer question had been discussed before and always put off. On the one hand it would be very handy in the flat, especially for email and the web, but on the other it was bulky and would be difficult to fit in, and Leon seemed reluctant to make the decision to shift it out of his old home. His mother, too, seemed unhappy about letting it go.

'Morarji has been using it, but I don't know how Leon's managed without it,' she said doubtfully. 'He's very attached to it. It was our birthday present to him last year.'

'I've been telling him we should get a laptop,' Kathy said.

'That would be very wasteful,' Ghita said disapprovingly, 'when he already has such a good machine.'

'But if Morarji is using it . . .'

'Oh nonsense. He only plays around on the web.'

It was obvious that Ghita was quite out of sorts about the whole business and, despite her husband's attempts to make amusing conversation, the rest of Kathy's visit was a subdued affair, made more painful by the labour of dismantling the computer in Leon's old bedroom and carting it down to the car. As she drove back towards Finchley, Kathy thought of Brock's suggestion that she imagine the mother as twenty years younger and male, but couldn't see Leon, or didn't want to.

He helped her carry the computer up to the flat on the fourteenth floor, and it was immediately apparent that it was going to be a problem. The flat was just too small, and there was nowhere to put it. In the end it had to be set up on one end of the table they used for eating and writing. The place was becoming impossibly cluttered, and despite her best efforts, Kathy felt herself showing her irritation.

'We'll have to get a bigger place,' she said, hearing the edginess in her voice. 'This is getting ridiculous.'

'Don't worry. We'll manage.'

Kathy caught herself angrily thinking of his mother's words: somebody's got to do the worrying. 'What's that stuff over there?' She pointed accusingly at a pile of bound doc.u.ments spilled untidily beside the sofa.

'All the forensic material on the Verge case. Brock sent it over to me. Wants me to review it and find if they missed anything.' He sounded exhausted and defeated by the prospect. 'I haven't got the time, Kathy. Look at it. I'm up to here at work, and I've got my first university a.s.signment due next week.'

This was why he needed the computer, of course, Kathy thought, and immediately her anger drained away. She went over and put her arm around him. 'Sorry, love. I'd forgotten about that. Can I help with the Verge files? You were involved at the beginning, weren't you?'

'Only for the first couple of weeks, then they moved me on to other cases.'

'Well, why don't you go through the technical stuff and I'll check the procedures. I know the drill.' As she said it she thought guiltily of the briefing doc.u.ments for the Crime Strategy Working Party that lay in her briefcase, unread.

He shook his head. 'No, I'll have to do it . . .' But over dinner he conceded that it might just be possible for her to help.

They settled themselves with coffee at opposite ends of the sofa, the reports piled between them, and began to work through them in silence. At midnight Kathy rubbed her eyes, yawning, and realised she had reread the same paragraph three times and still hadn't made sense of it.

'I think I've had it,' she said. 'This stuff is so boring.

What does this mean?'

She handed him the pa.s.sage.

He squinted at it, eyes heavy. 'It means that the following traces weren't matched.'

'Well, why don't they just say that?' She took the doc.u.ment back and turned to a schedule on an earlier page.

'There's quite a number of them, fingerprints and DNA. So that means they weren't matched to either Miki or Charles Verge?'

'What date was that?'

She checked the report. 'June the fourth. That's a long time after the murder, isn't it? Three weeks.'

'They identified Verge's prints early on, but they had trouble verifying his DNA. They had to get matches from his mother and daughter. They weren't a hundred per cent sure they had him till the end of May.'

'Well, if these samples weren't his or Miki's, whose were they?'

'The Verges did quite a bit of entertaining before he went off to the States, including a number of visitors from abroad. We weren't able to track them all down. There's a report on that somewhere, with a list of all the people who gave samples and were eliminated, including people like the cleaner and the two who discovered the body.'

Kathy turned pages until she found the list. 'Oh yes, there's over a dozen. What am I supposed to do with this?'

'Well, you could cross-check that list with the schedule of traces found in the apartment and make sure they're all accounted for, then see that any marked "check and refer" were properly followed up.'

She groaned. It would take ages, and this was just one small section. 'Brock shouldn't have put this on you, Leon.

He should have a team of drones going through it.' The briefing doc.u.ments for the Crime Strategy Working Party surely couldn't be more tedious than this, or more pointless, for they all knew that the forensic evidence had been singularly unhelpful.

'Come on,' Leon said, getting wearily to his feet. 'Let's go to bed.'

But an hour later Kathy was still awake, lying motionless at Leon's side while her brain, overtired and unable to shut down, nagged at the events of the day. She thought about the relationship between ambitious, protective mothers and their sons, and wondered if the sons then went on to become ambitious, protective fathers to their daughters.

She thought about Charlotte Verge, named after her father, and tried to imagine what sort of a mother she, in her turn, would become.

Finally she decided that she would have to get up and occupy her brain for a while if she were ever to get to sleep.

She slipped on a dressing gown and went back to the living room, depressingly untidy and crowded after their evening's work. Which would be more soporific, she wondered, the forensic or the committee papers? She remembered that the scene-of-crime reports had numbered the rooms in the Verge apartment on a computer-generated plan, and that the numbering went into double figures. That was the kind of place she and Leon needed. She opened the file and found the plan, trying to imagine how it would feel to live in such a place, then turned to the section of forensic schedules. If I get to the end of this section, she thought, I will at least have achieved something tonight. She took it over to the table, pushed the computer as far as it would go towards the window, and sat down.

Actually, it looked as if someone else had already checked the lists as Leon had suggested. On the photocopied pages there were pencilled ticks against most of the 'check and refer' items, a few of them circled. Trace number sixty-two, for example, was circled, but to find out what it was she had to refer to another schedule. She swore softly.

This was so complicated. Why didn't they keep it simple?

She established that trace sixty-two was a DNA sample taken from a pillowcase found in room seven, presumably a bedroom. She checked the plan and found that seven was in fact the utility room, and from a description of that room and its contents found that the pillowcase was one of a pair found in the washing machine, with a load of clothes.

There had been laundry powder in the machine, but it hadn't been switched on. The second pillowcase had also yielded a trace, number sixty-three, but when she checked it against the original schedule she found that it had been ticked by the unknown checker, not circled. Why? she wondered sleepily.

Like the rooms and the traces, the people who had been identified from the DNA and other evidence in the apartment had also been given numbers. Trace number sixty-three, Kathy discovered, was a smear of lipstick which had been found on the second pillowcase and which had been positively identified as belonging to individual number one, who, from another schedule, turned out to be the victim, Miki Norinaga.

Kathy found her attention wandering. The repet.i.tion of numbers and lists was mesmerising and she began to think she might return to bed. She turned back to the circled trace, number sixty-two, and began to follow its trail; room number seven, the washing machine, the first pillowcase, a DNA trace this time, and finally the matching individual, number four. She turned to the list of people and read the name, to her surprise, of Charles Verge's partner, Sandy Clarke. Both he and Jennifer Mathieson had been automatically asked for fingerprints and DNA samples in order to eliminate any they may have inadvertently left in the flat when they discovered the body. And now here he was, apparently laying his sweaty brow on a pillow beside Miki Norinaga, who hadn't removed her lipstick. Kathy felt a jolt of excitement.

She began to search for any other traces attributed to individual number four. They had found his fingerprints on the bedroom door, she discovered, and that was all; not a hint of DNA anywhere else. She racked her brain for an innocent explanation for the pillow traces, but couldn't think of one. Sandy Clarke surely must have been Miki Norinaga's lover.

But why hadn't they heard about this before? Kathy had been there when Brock had asked Clarke if Miki might have been having an affair, and she had heard him dismiss the idea. There had been no hint of it in the briefings they'd had, or in any doc.u.ment she'd seen. Had the information simply been overlooked, lost in all the mountains of data? If so, the person who should have checked and referred would be in very deep s.h.i.t. She gave a little shudder at the thought of Superintendent Chivers' reaction. Whoever it was would be crucified. She turned the pages to the end of the report.

On the final page was a heading 'Action', and the words, 'Refer identified items to LO, DS Desai'. The unknown penciller had underlined the words twice.

Kathy sat for some time staring out of the window, trying to think this through. She gazed unseeing at the chains of streetlights twinkling dimly into the distant darkness.

There was probably some unremarkable explanation. Leon was meticulous and methodical and surely wouldn't have overlooked anything like this. No doubt he'd asked for a further check of such an odd and isolated trace from individual four, and they'd discovered that it had been mixed up. Much more likely that it had belonged to individual two, Charles Verge. Somewhere further on in the piles of reports this would be recorded. Hopefully. She began to flick through the doc.u.ment pile for some sign of it, without success. Or maybe Leon was off the case when the referral was made, and the data had been lost by the laboratory liaison officer who took over from him.

His jacket was on the back of the other chair, and she knew he kept a small appointments diary in the inside pocket. She reached over for it and turned the pages back to the fourth of June. There was a note that read, 'K @ Bramshill all week', and she remembered that that was the week she'd been away on a course at the staff college. There were other notes for that and the following days; times and places of appointments, several marked 'PO'. Post office? It was impossible to tell whether they related to the Verge inquiry or other cases.

As she returned the diary to the jacket pocket another horrible thought occurred to her. She had complained to Leon that Brock should have got someone else to do this drudgery. Perhaps he already had. Perhaps the penciller had been working for Brock, and had informed him of the circled items that had never been followed up. Was this Brock's way of giving Leon a chance to redeem or hang himself?

She checked her watch. One thirty-five. She picked up the report and opened the bedroom door, hearing the rhythmic sigh of Leon's breathing. 'Sorry, lover,' she murmured, and stroked his shoulder. He came awake slowly, blinking, as if she'd pulled him out of a deep, dark hole.

When she explained what the time was and that she'd found something that couldn't wait till morning, he stared at her in disbelief, struggling to follow her words.

'A pillow?'

'Two pillowslips, Leon. Miki on one and Clarke on the other. And they weren't sleeping.'

'How do you mean?' Leon was rubbing his face, trying to clear his head.

'She had lipstick on.'

'What about the sheets?'

'They must have been washed in the previous load, don't you think? And this must have happened not long before the murder; well, within twenty-four hours, surely?

Someone loaded the machine and then was distracted and didn't start it up.'

Leon shook his head. 'This is new? How come this hasn't come out before now?'

'Exactly.' The decisive way she said this made him sit up. She handed him the last page of the report.

'Oh.' He stared at the incriminating words, then finally said, 'I'm sure I've never seen this. I think I was off the case by then. What date was it?'

'June the fourth. That was the start of the week I spent at Bramshill.'

'Oh yes . . .' He covered his eyes with his fingers and rubbed. 'I remember.'

'Do you want your diary, to see what case you were working on then?'