“What about Paul Ryder?” Banks asked.

“Who?”

“Paul Ryder. Christine’s birth father, remember? We haven’t been able to find him.”

Frances looked down at the scarred tabletop and ran her fingertips over its rough surface.

“There was no Paul Ryder, was there?” Banks said.

She responded with a barely perceptible shake of the head.

“Patrick was Christine’s real father, wasn’t he?”

“Yes,” she said, still looking down at the table.

“Remember when we first met, when Patrick wanted to drive you to Eastvale to identify the body?”

Frances just looked at him.

“You said, ‘She’s my daughter.’ I took it to imply that you were putting him in his place, reminding him that he was only Christine’s stepfather, but that wasn’t it, was it?”

“When you live a lie for long enough,” Frances said, in little more than a whisper, “you come to believe it.”

Banks let the silence stretch, with only the hiss of the tape and muffled sounds from the station in the background, then he looked at Bridges, who shook his head slowly. “Let’s suspend this interview for now,” Banks said. Bridges nodded and turned off the tape machine.

“Alan out again, is he?” asked DS Stefan Nowak, popping his head around the squad room door close to lunchtime that day.

“Another fire,” Annie said. “In Leeds, this time. I’ve just been on the phone with him, and it seems that Mrs. Aspern, the doctor’s wife, has killed her husband and tried to set fire to the body.”

Stefan whistled between his teeth.

“Indeed,” saidAnnie. “Have you got anything new for us?”

“I might have.” Stefan walked into the room and sat down opposite Annie. He looked as handsome and regal as ever, and just as remote and unreadable. Not for the first time, Annie wondered what sort of private life he had. Did he have friends outside the force? Family? Was he gay? She didn’t sense that in him, but she had been wrong before.

Stefan opened the folder he had brought with him. “What do you want first,” he asked, “the good news or the bad news?”

“I don’t care,” Annie said.

“Well,” Stefan went on, “apart from the soil and gravel samples, which do match samples from the lay-by, we drew a blank with the Jeep Cherokee. The car rental company had done a bloody good job of cleaning it, inside and out. We did find some hair, fibers and a partial print under the front seat, but it’s not much more than a smudge. We might be able to do some computer enhancement, but don’t expect too much.”

“That’s pretty well what I figured,” said Annie. “I wouldn’t be surprised if our killer gave it a good going over, too. He seems to be the meticulous type.”

“And we checked a sample of petrol from the fuel tank of Leslie Whitaker’s Jeep Cherokee with the accelerant from the Gardiner fire.”

“And?”

“It doesn’t match.”

“Shit,” said Annie.

“We do have the Nike trainer impression, though. That’s pretty distinctive. If he hasn’t ditched them, we can match them when we find a suspect.”

“Was that the good news or the bad news?”

Stefan smiled. “It might be nothing, but one of our lads found traces of candle wax puddled near the point of origin in Roland Gardiner’s caravan.”

“You mean he’d been having a romantic evening?”

“No,” said Stefan, “that’s not what comes to mind. Not my mind, anyway. Call me a cynic, but I see it in a different light altogether.”

“Joke,” said Annie. “Never mind. Wasn’t there also a candle beside the girl who died on the boat?”

“Yes,” said Stefan, “but that’s different. The fire didn’t originate on the boat, and it was pretty clear she’d used the candle to prepare the heroin she’d injected. Also, the boyfriend said in his statement that he made sure the candle was out before he left.”

“Mark Siddons? I can’t understand why everybody is so quick to believe anything he says. He could easily have been lying.”

“No, this is something else.”

“I think I know what you’re getting at,” said Annie.

“Yes. It looks as if it was used as some sort of primitive time-delay ignition device. It’s not unusual in arson cases.”

“So the killer makes sure Gardiner’s fast asleep, pours out the petrol, then lights the candle and leaves?”

“And an hour, or two hours later, the candle burns down, meets the petrol, and puff! Up it goes.”

“Can you estimate how long?”

“If we can discover exactly what make and length of candle it was, and if we assume it hadn’t been used previously, was still whole, then yes. But don’t hold your breath. We don’t have a lot to go on.”

“An estimate?”

“Well, an ordinary household candle is seven-eighths of an inch in diameter, and it burns one inch every fifty-seven minutes in a draft-free environment.”

“The caravan could hardly have been a draft-free environment, could it?”

“Agreed,” said Stefan. “But there was hardly any wind that night. Anyway, let’s say you’ve got a six-inch candle, that gives you nearly six hours of burn time before ignition, all factors being equal.”

“How could the killer rely on Gardiner’s remaining unconscious for that long?”

“He couldn’t. Look, Annie, it could have been just a candle stub. Half an inch, an inch. Half an hour, or an hour at the most.”

“Or it could have been two hours, or three?”

“Afraid so. It could even have been one of those fancy thick candles, which would burn much more slowly. We’re doing what tests we can on the wax, but as I said, don’t get your hopes up.”

“What about Thomas McMahon’s barge? Anything there?”

“No signs of candle wax. It looks as if that fire was set directly.”

“But not the Gardiner fire?”

“No.”

“Isn’t using a candle like that unreliable?”

“Extremely. Very crude and unpredictable. Not to mention dangerous. Any number of things can, and do, go wrong. You could accidentally ignite the accelerant when you’re lighting the candle, for example. Or you light it and leave and a draft blows it out. Or it topples over and sets the accelerant off sooner than you’d hoped. It’s amateur, but it can also be very effective, if it works. I’m sorry it’s not very much to go on,” Stefan apologized, “but it does tell us one thing, doesn’t it?”

“Yes,” said Annie, already turning over the implications in her mind. “It tells us that whoever set the second fire needed time, most likely time to arrange for an alibi. And which of our suspects seems to have a watertight alibi?”

Stefan thought for a moment, then answered. “Leslie Whitaker?”

“Exactly.”

“But what about the petrol?”

“He must have been bright enough to siphon some from someone else’s car. Maybe he knew there was a chance we’d be able to trace it. Don’t you see, Stefan? It makes sense. Whitaker said he went out for an eight-o’clock dinner in Harrogate with nine other booksellers. They all vouched for him. We already know that he supplied Thomas McMahon with the special paper he needed to produce his forgeries. They were in it together. He practically admitted as much. One reason we almost ruled Whitaker out was that he’s got an alibi for the Jennings Field fire, but not the one on the barges.”

“But this timing device puts paid to his alibi?”

“Yes,” said Annie. “If he was in Harrogate for that dinner at eight o’clock, then he must have left Eastvale, or Lyndgarth, where he lives, at about seven. But surely it would have been possible for him to use a two-or three-inch candle and gain a couple of hours or more burn time before the accelerant ignited?”

“Easily, assuming it all went according to plan.”

“This time it did,” said Annie. “We’ll have him in, Stefan. And then we’ll have him.”

After the interview with Frances Aspern, Banks picked up a coffee in the canteen and remembered that he had intended to ring Dirty Dick Burgess. He found an empty office and took out his mobile.