imited options flashed across Lindsay's mind as cold sweat sprang out along her spine. Her escape route was cut off by the man filling the stairwell behind her. She could whirl round and catch him off guard, banking on one swift push toppling him and being able to get clear by jumping over him. She could pretend to be connected to the police, mutter something obscure, finish locking up and leave. Then she remembered Sandra Bloom's briefing what felt like weeks ago. The murder had been discovered by the upstairs neighbour. Since this was probably the man who had found Penny's body, she realized that whatever she did, she needed to find a way to talk to him.

Lindsay swung round and gave an alarmed smile to the man, who stood frowning a couple of steps below the landing. A thatch of greying, mousy hair jutted out above a high forehead that narrowed to a pointed chin. Round, intelligent, blue eyes flanked a beaky nose that overhung a small, feminine mouth whose lower lip bore the indentations of two front teeth. He reminded Lindsay irresistibly of a cartoon octopus.

"God, you nearly gave me a heart attack," she said as lightly as she could manage while desperately dredging her memory for his name.

"Sorry," he said automatically. "I just wondered what was going on. That's a crime scene, you know."

"That's why I was in there," Lindsay said, holding up her gloved hands for his inspection. "Just checking up on one or two details for my boss." She grinned disarmingly, still reaching for a name.

"You're with the police?" he asked, an edge of suspicion in his voice.

"How else would I have the keys?" she parried. If she managed to avoid making any firm statement, it would be that much harder afterwards to make a case against her for impersonating a police officer. "I wish everyone was as civic-minded as you, Mr. Knight." She'd summoned up a mental picture of the names by the bells on the front door jamb; she prayed she'd gone for the right one.

The man relaxed visibly. She'd got it right, and her knowing his name immediately made the rest of the scenario credible, even though it was a picture almost entirely of his own painting. He smiled back at her. "Well, you can't be too careful, can you? How's the investigation progressing? I heard on the news that you'd released the woman you were questioning."

"That's right. We need to build a more solid case before we can think about charging anyone."

"I can imagine," he said. "But you're pretty sure you've got the right person, are you?"

Lindsay winked. "Obviously that's not something I could comment on, sir. But we're not expanding our circle of inquiries any wider just as yet, if you get my meaning."

"I only wish I'd actually seen her leave, been more help," he said wistfully.

"You've been very helpful already, sir. Without your intervention, who knows how long Ms. Varnavides might have been lying there?"

He shrugged, his expression a cross between smug self-satisfaction and embarrassment. "I'm a great believer in taking social responsibility."

Now she remembered another snippet from Sandra's briefing. Derek Knight was a manager in one of the new hospital trusts. As caring as Mr. Gradgrind, if what she'd read in her imported Guardian Weekly about the new breed of health service bosses was anything to go by. "I suppose you have to be, in your job," Lindsay smarmed. "Actually, I was hoping to catch you. There were just one or two points I needed to clarify with you."

"Was there some problem with my statement?" he asked anxiously.

"No, no problem at all. It's just that in the light of subsequent interviews, my boss wanted me to come back and go over some of the details in your statement. Just to check there's no possibility of error."

He nodded magisterially. "I understand. Iron out any potential contradictions."

"I wouldn't say contradictions, exactly..." Lindsay hedged. "Perhaps if we could go upstairs? More private than here?"

"Of course, of course. If I could just... ?"

Lindsay squeezed into the corner to allow him to pass her and turn the corner to the upper flight of stairs. She followed him into a flat whose layout was similar to the one below, save that Derek Knight had left the wall of the corridor intact. Combined with the lower ceilings of the top floor, it made his living room seem significantly smaller and more claustrophobic than Brian and Miriam's, an impression compounded by the dark brocade curtains and upholstery. The room managed to be both fussy and impersonal.

It looked like the province of a much older person, as if it had been decorated and furnished by his mother, and he hadn't dared impose his own personality on it, Lindsay thought.

Knight dropped his briefcase by the door and gestured toward one of two wing chairs facing each other across a gas fire that was the double of one Lindsay had lived with as a student nearly twenty years before. It hadn't been new then. Beside it, incongruously, was a set of antique brass fire irons. Obediently she sat, and he settled in opposite.

"You'll have to bear with me," Lindsay said. "I only had the sketchiest look at your statement before the boss whipped it off me, so I'm probably a lot less au fait with what went on the other night than you are."

"Well, as you'll have seen from its brevity, there wasn't a great deal your colleagues considered to be significant," he said primly.

"You came home at... what time would it have been?"

"The usual time. Just like tonight."

"So... around half past seven?"

"Between twenty-five and half past seven. It depends on the tube."

Lindsay nodded, her notebook out and her pen scribbling. "And you noticed nothing at the street entrance to indicate there might be any problem, is that right?"

"No, no, that was the first sign that things were not as they should be. I said so in my statement," he said plaintively, as if dealing with a stupid and recalcitrant child.

Thinking furiously, Lindsay gave it her best shot. "The lock?" she hazarded.

"Exactly. The mortise was unlocked. It was only the Yale that was engaged. As if someone without a key had just slammed the door shut behind them. Well, I knew the Thomases on the ground floor wouldn't dream of leaving themselves so vulnerable. I had had occasion to mention the importance of it to Ms. Varnavides, but since then she'd been quite reliable about it, so I was rather upset." He pursed his lips and sighed through his nose. "I assumed she'd just been remiss again. As I think you were today?"

Lindsay looked surprised, recalled she hadn't locked a mortise behind her as she'd come in, and smiled sheepishly.

"I thought as much. Of course, I had no idea there was more to it than carelessness."

"Of course not," Lindsay said, trying to keep the irritation out of her voice. "Thinking back, was there anything that struck you as being out of place? Sometimes, with the passage of time, things become clearer to us..."

Knight crossed his legs at the knee, revealing an inch of bony, milk-white leg between grey sock and grey trouser cuff. He knitted his fingers together in his lap and pondered, clearly revelling in self-importance. "Nothing springs to mind," he eventually said reluctantly.

"Never mind. So you climbed the stairs and saw..."

"The door to the Steinbergs' flat was open." He gave a tight little smile, as if imagining the impact when he imparted this in the witness box.

"When you say open, do you mean ajar, or standing wide open, as if someone had flung it back?"

A momentary flicker of a frown tugged at the skin round Knight's eyes. "Are you sure you read my statement?"

Lindsay willed herself to relax and smiled. "Like I said, I just had time to glance at it. We like to do these followup interviews without too many preconceptions. A fresh eye on the subject, you know?"

"Hmmm. Waste of time, more like," he muttered. "I wouldn't stand for a wash of resources like this in my hospital."

"The door?" Lindsay prompted, biting back a sharp comment about patients being shunted from one hospital to another in the futile search for an intensive care bed before they died in the attempt.

"It was half-open. Considerably more than ajar, but not wide open."

"As if someone had come out in a hurry?"

He pulled a face Lindsay recognised. It was the same one her chemistry teacher had used whenever he'd been asked a question he didn't really know how to answer. "I wouldn't really have thought so," he eventually said. "The Steinbergs have one of those thick-pile carpets in the hall, so the door doesn't swing free. If someone had yanked it open in a rush, it would have been wider than it was."

Lindsay filed the incongruous detail away for further consideration, marking it with an asterisk in her notes. "So, being a good neighbour, you went in?"

"I knocked on the door," Knight corrected her. "I called out, but there was no reply. I was starting to feel a little concerned."

"And so you went in?" Lindsay prodded.

He nodded, a prurient gleam in his eye. "I knew something was wrong as soon as I got inside. The place smelled like a brewery crossed with a butcher's shop. I could see there was nothing amiss in the lounge, but when I got to the kitchen doorway... Well, I don't have to tell you what it was like," he said, an obviously spurious delicacy giving him pause.

"Just for the record?" Lindsay asked, pen poised.

"Blood everywhere. On the floor, on the walls, all over the worktops. And glass. There was broken glass scattered around. And in the middle of it all, Miss Varnavides. It was obvious she was dead. No one could lose that much blood and still be alive."

There was no compassion in his voice, Lindsay thought bitterly, only the self-satisfied confidence of a man who thinks he knows what he's talking about. "Indeed," she said, her voice dry and emotionless. "Did you actually go across the threshold into the kitchen?"

"Of course not. These days everybody knows you mustn't interfere with the scene of a crime, and I could see that something terrible had happened. I assumed some intruder had hit her with a broken bottle. That was the only explanation I could come up with, seeing all the blood and the glass. Your people thought it was an accident. But it turns out I was right after all." He smirked.

"Mmm," Lindsay said noncommittally. "So you came upstairs and called the police?"

"Well, yes. I didn't want to use the phone down there in case the last number Miss Varnavides had called was a clue."

"Not very likely if she'd been killed by an intruder," Lindsay said quietly as she made a note.

"She might have been trying to call the police," he said defensively. "She might have panicked and rung 911 instead of 999, being American."

It was, she supposed, a reasonable point. "And then our lads arrived," she said.

Knight gave her a curious look. "Sorry?"

"And then our lads arrived. The police. After your 999 call. The boys in blue."

"That's right," he said slowly. "Very quick off the mark, your detective inspector."

Lindsay smiled. "He doesn't hang around."

Knight got to his feet. "I'm sorry," he said. "I'm being very inhospitable here. I just realised how thirsty I am. You must be too, in this heat. Can I get you anything? Tea? Coffee? Mineral water?"

Lindsay shook her head. "I'm fine, thanks. I'll need to be on my way soon. I've just got a couple more questions about visitors to the flat..."

"I'll be right back, if you'll just bear with me a moment." He cleared his throat noisily. "Desperate for a cup of tea. Terrible frog in my throat." Knight smiled ingratiatingly as he sidled out of the room, closing the door behind him.

Lindsay sat still for a moment, wondering what she'd said to unsettle Knight so obviously. Then, faintly, she heard the electronic exclamations of a touch-tone telephone. "Ah, shit," she murmured, stealthily easing out of the chair and edging toward the door. Half-way there, she noticed there was a phone on a side table just within reach of Derek Knight's preferred armchair.

She sidestepped the chair and reached for the phone. One hand gripped the handset, the other wormed its way under the earpiece until it was pressed down over the black plastic trigger that replaced the old-fashioned cradle. She lifted the handset to her ear, still keeping the trigger firmly depressed. She wrestled one-handed with the handset until her thumb was pressed hard against the mouthpiece, effectively cutting off any external sound, then put the earpiece to her ear. With slow and infinite care, Lindsay gently and gradually released the black trigger.

Derek Knight's voice was loud in her ear, waspishly impatient "... asked to be put through to Inspector Nicholson."

"This is Detective Constable Partridge, sir. I'm one of the inspector's team. How can I be of help?" A more distant voice rumbled. Lindsay's chest tightened. If Knight was calling the police, there could only be one reason. He'd sussed her.

"I don't wish to appear rude, officer, but I've already had dealings with Inspector Nicholson on the Varnavides case, and it would save time all round if you'd just put me through to the correct extension."

Good sense would take her feet out of there as fast as they could go, Lindsay knew. But good sense had never been her first choice when curiosity was one of the other available options. She wanted to know what had triggered Derek Knight's suspicions of her. Then she'd leave, and only then.

"I'm afraid that won't be possible," DC Partridge said, his voice placatory. "Inspector Nicholson isn't in the station right now."

"When will she be back? This is urgent, officer!"

She, Lindsay thought ruefully. What a time for her to be hoisted on the petard of sexist assumption. The police had been "the lads" for so long, it hadn't occurred to her that the officer in charge of a murder hunt could be a woman. And everybody else had been so busy being politically correct that no one had mentioned it to her.

Lindsay was so busy mentally cursing herself that she missed the officer's reply. But she heard Derek Knight's response loud and clear. "Well, in that case, you'll just have to do. Are you familiar with the Varnavides case?"

"I'm the officer who took your statement, Mr. Knight," Partridge said heavily.

"Fine. Well, I've got a woman in my flat impersonating a police officer. I caught her coming out of the murder scene and when I challenged her, she claimed to be with the police. She said she had some more questions for me, but I was suspicious. Then I tricked her into revealing that she thought Inspector Nicholson was a man."

"And this person is still in your flat, sir?" Suddenly Partridge sounded alert and interested.

"Oh, yes."

"Do you think you can keep her talking until we can get a car there?"

"No need for that, officer. I've locked her in."

Lindsay closed her eyes and swore silently. Then she gently depressed the phone button and replaced the receiver as silently as she possibly could. She crept to the door and depressed the handle. Nothing happened. Derek Knight hadn't lied. She was locked in his living room three floors above the Islington street.