Hamilton took a small gadget from his accessory bag, bent and pointed a tube at the floor. “It’s a hydrocarbon detector, technically known as a sniffer,” he explained. “It should tell us whether accelerant has been used and…” He flicked a switch. “Indeed it has.”

Hamilton instructed Terry Bradford to use his trowel and shovel two or three liters of debris into a doubled nylon bag and seal it tight. “For the gas chromatograph,” he said, sending Bradford to other parts of the room to do the same thing. “It looks as if it’s multi-seated,” he explained. “If you look at the pattern of burning closely, you can see more than one fire occurred in this room, linked by those deeply charred narrow channels, or streamers, as they’re called.”

Banks knew that a multi-seated fire was an indication of arson, but he also knew he wouldn’t get Hamilton to admit it yet. Peter Darby handed him the camcorder and clicked away with his Pentax. “Hasn’t the water the firefighters used got rid of any traces of accelerant?” Darby asked.

“Contrary to what you might imagine,” said Hamilton, “water cools and slows the process down. It actually preserves traces of accelerant. Believe me, if any was used, and the sniffer indicates that it was, then it’ll be present in these bits of carpet and floorboards.”

Terry Bradford bent to remove some debris and uncovered the mostly blackened human shape that lay twisted on its stomach on the floor. It was impossible to tell whether it was a man or a woman at first, but Banks assumed it was most likely the man known to Mark only as Tom. Though he looked quite short in stature, Banks knew that fires did strange and unpredictable things to the human body. A few tufts of reddish hair still clung to the cracked skull, and in some places the fire had burned away all the flesh, leaving the bone exposed. It was still possible to make out patches of a blue denim shirt on the victim’s back, and he was clearly wearing jeans. Banks felt slightly sick behind his particle mask. “That’s odd,” said Hamilton, stooping to look at the body more closely.

“What?” said Banks.

“People usually fall on their backs when they’re overcome by flames or smoke inhalation,” Hamilton explained. “That’s why you often see the knees and fists raised in the ‘pugilistic’ attitude. It’s caused by the contraction of the muscles in the sudden heat of the blaze. Look, you can see the pooling where the accelerant trickled into the cracks of the floor around the body. Probably under it, too. The charring’s much deeper around there and there’s far more general destruction.”

“Tell me something,” said Banks. “Would he have had time to escape if he’d been conscious and alert when the fire started?”

“Hard to say,” said Hamilton. “He’s on his stomach, and his head is pointing toward the source of the fire. If he’d been trying to escape, he’d most likely have been running or crawling away, toward the exit.”

“But could he have got out, if he’d seen it coming?”

“We know a part of the ceiling fell on him. Maybe that happened before he could escape. Maybe he was drugged, or drunk. Who knows? You’ll not get me speculating on this. I’m afraid you’ll have to wait till the postmortem and toxicology screens for answers to your questions.”

“Any signs of a container or igniter?”

“There are plenty of possible containers,” said Hamilton, “but not one with ACCELERANT written in capital letters on it. They’ll all have to be tested. Odds are he used a match as an igniter, and sadly there won’t be anything left of that by now.”

“Deliberate, then?”

“I’m not committing myself yet, but I don’t like the looks of it. It’s hard to predict what happens with fires. Maybe he was drunk and spilled some accelerant on his clothes and set fire to himself and panicked. People do, you know. I’ve seen it before. And smoke inhalation can cause disorientation and confusion. Sometimes it looks as if people have run into the flames rather than away from them. Let’s just call it doubtful origin for now, okay?”

Banks looked at the blackened figure. “If the doctor can tell us anything from what’s left of him.”

“You’d be surprised,” said Hamilton. “Rarely is a body so badly damaged by fire that a good pathologist can’t get something out of it. You’ll be having Dr. Glendenning, I imagine?”

Banks nodded.

“One of the best.” Hamilton instructed Terry Bradford to take more samples, then they moved toward the bow of the barge, to the point where it almost touched its neighbor’s stern. They waited while Peter Darby changed the film in his camera and the cassette in his camcorder.

“Look at this,” Hamilton said, pointing to a clearly discernible strip of deeply charred wood that started in the living quarters, near the main seat, and continued to the bow, then over to the stern and living quarters of the other boat. “Another streamer,” he said. “A line of accelerant to spread a fire from one place to another. In this case, from one barge to another.”

“So whoever did this wanted to burn both barges?”

“It looks like it.” Hamilton frowned. “But it’s not very much. Just one narrow streamer. It’s like… I don’t know… a flick of the wrist. Not enough. An afterthought.”

“What are you getting at?”

“I don’t know. But if someone had really wanted to make sure of destroying the second boat and anyone on it – and I’m not saying that’s what happened – then he could have done a more thorough job.”

“Maybe he didn’t have time?” said Banks.

“Possible.”

“Or he ran out of accelerant.”

“Again, it’s a possible explanation,” said Hamilton. “Or maybe he simply wanted to confuse the issue. Either way, it cost another life.”

The body on the second barge lay wrapped in a charred sleeping bag. Despite some blistering on her face, Banks could see that it was the body of a young girl. Her expression was peaceful enough, and if she had died of smoke inhalation, she would never have felt the fire scorching her cheeks and burning her sleeping bag. She had a metal stud just below her lower lip, and Banks imagined that would have heated up in the fire too, explaining the more deeply burned skin radiating in a circle around it. He hoped she hadn’t felt that, either. One charred arm lay outside the sleeping bag beside what looked like the remains of a portable CD player.

“The body should be fairly well preserved inside the sleeping bag,” Hamilton said. “They’re usually made of flame-resistant material. And look at those blisters on the face.”

“What do they mean?” Banks asked.

“Blistering is usually a sign that the victim was alive when the fire started.” Making sure that Peter Darby had already videotaped and photographed the entire scene, Hamilton bent and picked up two objects from the floor beside her.

“What are they?” Banks asked.

“Can’t say for certain,” he said, “but I think one’s a syringe and the other’s a spoon.” He handed them to Terry Bradford, who put them into evidence bags, taking a cork from his accessory bag first, and sticking it over the needle’s point. “The fire’s sure to have sterilized it,” he said, “but you can’t be too careful handling needles.”

Hamilton bent and scraped something from the floor beside the sleeping bag and Bradford put it in another bag. “Looks like she was using a candle,” Hamilton said. “Probably to heat up whatever it was she injected. If I wasn’t so certain the fire started on the other barge, I’d say that it could have been a possible cause. I’ve seen it more than once, a junkie nodding off and a candle starting a fire. Or it could even have been used as a crude timing device.”

“But that’s not what happened here?”

“No. The seats of the fire are definitely next door. It’d be just too much of a coincidence if the two fires started simultaneously from separate causes. And this one caused so much less damage.”