Rickards kicked the door gently, looking away. He said: 'Bloody hell, I'd forgotten. Sorry. Wrong time to ask, for both of us.'

There were confident footsteps mounting the stairs and now they had reached the passage. Dalgliesh said: 'It sounds as if the pathologist has arrived.'

Rickards made no reply. He had moved over to the chest of drawers and, with his forefinger, gently urged the tangle of hairs across the polished wood.

He said: 'There's one sample which we won't find here. Hilary Robarts. Forensic will look to make doubly sure, but it won't be here. And now I start looking for a very different murderer. And, by God, Mr Dalgliesh, this time I'm going to get him.'

Forty-five minutes later Rickards was back at the scene of the murder. He seemed to have passed beyond conscious tiredness and to be operating in a different dimension of time and space in which his mind worked with unnatural clarity while his body had become almost weightless, a creature of light and air, as insubstantial as the bizarre scene in which he moved and spoke and gave his orders. The pale transparent disc of the moon was eclipsed by the glare of the mounted lights which illumined and solidified the hard outlines of trees and men and equipment, yet paradoxically robbed them of form and essence so that they were, at one and the same time, revealed and clarified and transformed into something alien and strange. And always, beyond the masculine voices, the scrunch of feet on pebbles, the sudden flap of canvas in a tentative breeze, was the continual fall and suck of the tide.

Dr Anthony Maitland-Brown had driven from East-haven to the scene in his Mercedes and had arrived first. He was already gowned and gloved and crouching by the body by the time Rickards caught up with him. Wisely he left him to it. M-B strongly disliked being watched while he made his preliminary examination at the scene and was apt to protest with a peevish 'Do we really need all these people standing around?' if anyone came within ten feet of him, as if the police photographer, scene-of-crime officer and forensic biologist were all so many snap-happy sightseers. He was an elegant and extraordinarily handsome man, over six feet tall, who had once in youth – so it was rumoured – been told that he looked like Leslie Howard and had spent subsequent years sedulously promoting the image. He was amicably divorced, comfortably well-off-his mother had bequeathed him a private income – and well able to indulge his twin passions of clothes and the opera. In his free time he escorted a succession of young and extremely pretty actresses to Covent Garden and Glyndebourne, where they were apparently content to endure three hours of boredom for the prestige of his company or, perhaps, the frisson of knowing that the elegant hands which poured their wine or helped them out of the Mercedes were commonly engaged with more bizarre activities. Rickards had never found him an easy colleague but recognized that he was a first-class forensic pathologist, and God knew they were rare enough. Reading M-B's lucid and comprehensive autopsy reports he could forgive him even his aftershave.

Now, moving away from the body, he stirred himself to greet the recent arrivals, photographer, cameraman, forensic biologist. The stretch of beach fifty yards each side of the murder scene had been efficiently roped off and plastic sheeting laid over the path now lit by a string of overhead lights. He was aware of his sergeant's disciplined excitement at his side.

Stuart Oliphant said: 'We've found a print, sir. About forty yards into the copse.'

'On grass and pine needles?'

'No, sir, on sand. Someone, a kid perhaps, must have tipped it from a bucket. The print's a good one, sir.'

Rickards followed him into the wood. The whole of the path had been protected but at one place a marker had been driven into the soft ground at the right-hand side. Sergeant Oliphant drew back the plastic then lifted the box covering the print. In the glow of the overhead lights slung along the path it showed clearly, a dusting of moist sand over the pine needles and flattened grass, covering no more than six inches by four, and printed on it the intricate pattern of the sole of a right shoe.

Oliphant said: 'We found it soon after you left, sir. Only the one, but it's pretty clear. The photographs have been taken and the measurements will be at the lab this morning. Size ten by the look of it. They'll be able to give us confirmation pretty quickly, but it's hardly necessary. It's a trainer shoe, sir. A Bumble. You know the make, the one that has a picture of a bee on the heel. And it has the outline of a bee on the sole. You can see the curve of the wing here, sir. It's quite unmistakable.'

A Bumble trainer. If you wanted a print you could hardly hope for anything more distinctive. Oliphant voiced his thoughts: 'Common enough, of course, but not all that common. Bumbles are the most expensive on the market, the Porsche of trainers. Most of the kids with money like to have them. It's a bloody silly name. Part of the firm is actually owned by a man called Bumble and they've only been on the market for a couple of years, but he promotes them fairly vigorously. I suppose he hopes that the name will catch on, that people will start yelling for their Bumbles as they do for their wellie-boots.'

Rickards said: 'It looks fresh enough. When did we last get rain? Late on Saturday night, wasn't it?'

'About eleven. It was over by midnight but it was a heavy shower.'

'And there's no tree cover on this part of the path. The print's perfectly smooth. If it were made before midnight on Saturday I'd expect some spotting. Interesting that there's only the one and that it's pointing away from the sea. If someone wearing Bumble trainers came along this path any time on Sunday you'd expect to find at least one similar print on the upper reaches of the beach.'

'Not necessarily, sir. The shingle comes up almost as high as the path in places. We'd get no prints if he stayed on the pebbles. But if it was made on Sunday before she died would it still be here? She must have come along this path.'

'No reason why she would have trodden on it. It's well to the right of the path. It's odd, though. Too plain, too distinctive, too opportune. You could almost believe it's been deliberately made to deceive us.'

'They sell Bumble trainers at the sports shop in Blake-ney, sir. I could send a chap to buy a pair of size ten as soon as they open.'

'See that he's in plain clothes and buys them as an ordinary purchaser. I need confirmation of the pattern before we start asking people to turn out their shoe cupboards. We're going to be dealing with intelligent suspects. I don't want a balls-up at the beginning of the case.'

'Pity to waste time, sir. My brother owns a pair of Bumbles. The print's unmistakable.'

Rickards said obstinately: 'I need confirmation, and I want it fast.'

Oliphant replaced the box and the plastic cover then followed him back to the beach. Rickards was uncomfortably aware of the almost physical weight of resentment, antagonism and slight contempt which seemed to flow from the sergeant. But he was lumbered with the man. Oliphant had been part of the team bearing the brunt of the Whistler investigation and, although this admittedly was a different inquiry, it would be difficult to replace him without causing personal or logistical problems which Rickards was anxious to avoid. During the fifteen-month hunt for the Whistler his mild dislike of the sergeant had grown into an antipathy which he knew to be not wholly reasonable and which he had tried to discipline both in the interests of the investigation and of his own self-regard. A serial murder was difficult enough without personal complications.

He had no real evidence that Oliphant was a bully; he only looked like one. He was six feet of disciplined flesh and muscle, dark and conventionally handsome with rather pudgy features, full-lipped and hard-eyed, with a fleshy chin like a doughnut, dented in the middle with a deep dimple. Rickards found it difficult to keep his eyes off it. His repugnance to the man had elevated it to a deformity. Oliphant drank too much but that was an occupational hazard for a policeman. The fact that Rickards had never seen him actually drunk only increased the offence. A man shouldn't be able to put away that amount of alcohol and still stand firmly on his feet.