Simon Beckett - Written in Bone

‘That man is a royal pain in the arse.’

I’d been thinking along the same lines myself. ‘Come on, let’s get the evidence bags inside,’ I said.

I had an unpleasant conversation with Wallace while Brody and Duncan carried the evidence bags of bone and ashes into the clinic. Word had belatedly reached the detective superintendent that we’d been trying to contact him. Unfortunately, he’d called Fraser rather than Duncan, and the sergeant had lost no time in giving his side of events.

Consequently, Wallace was incandescent, demanding to know why we’d violated a crime scene without his permission. In no mood to be shouted at, I angrily pointed out that we’d had no choice, and that none of this would have happened if he’d sent SOC in the first place.

It was Brody who calmed things down, taking the radio to talk to Wallace out of earshot. When he handed it back to me, the superintendent was grudgingly apologetic. He told me to go ahead and continue my examination of the remains.

‘I suppose now you’ve got this far, you might as well see what else you can find out,’ he said, ungraciously.

The gesture was little more than an olive branch, as we both knew there was precious little I could do without a properly equipped laboratory. But I said I’d do my best. Before Wallace hung up, I asked what the situation was with the train crash. I’d not heard any news since I’d been on Runa, and I was out of touch.

The superintendent paused. ‘It was joyriders. They stalled the van on the line and then panicked and ran off.’

Not a terrorist attack after all, then. People had died, and SOC prevented from coming to Runa, all because some bored teenagers had stolen a van.

I was thinking about that as I returned to the clinic. Duncan was gingerly putting the dead woman’s hand into the fridge, holding it out at arm’s length. In the plastic of the evidence bag, it looked unsettling like a cut of meat for the freezer.

‘Still can’t get my head round how this happened,’ he said, closing the fridge door with relief. ‘How the body was burned, I mean. Just doesn’t seem natural.’

‘Oh, it was natural, right enough,’ I said, still brooding over what Wallace had said.

Both Duncan and Brody looked at me.

‘You know what caused it?’ Brody asked.

I’d known almost from the moment I set eyes on the remains. But I hadn’t wanted to commit myself until I’d been able to confirm my theory. Now, though, with the island cut off and half of the evidence buried under the cottage, there didn’t seem any reason not to tell them.

‘Pretty much,’ I said. ‘I gave you a clue the other day, Duncan, remember?’

‘The fatty stuff on the cottage ceiling, you mean? Aye, but I still haven’t been able to work it out.’

He looked embarrassed. Brody was watching me, waiting.

‘It comes down to two things. Body fat and what she was wearing,’ I explained. ‘Have either of you heard of something called the wick effect?’

They both looked blank.

‘There are two ways to reduce a human body to ash. You either incinerate it at a very high temperature, which didn’t happen here or the entire cottage would have burned down. Or you burn it at a lower temperature, for longer. We’ve all got a layer of fat just under the skin, and fat burns. Candles used to be made of tallow made from rendered animal fat before paraffin wax was used instead. So what happens is that, in certain conditions, the human body effectively becomes a giant candle.’

‘You’re joking,’ Brody said. For once the ex-policeman seemed rattled.

‘No. That’s why the residue on the ceiling and ground around the remains was significant. The fat liquefies in the heat and gets carried in the smoke. Obviously, the more body fat a person has, the more fuel there is to burn. Judging from how much was on the ceiling at the cottage, the dead woman had quite a lot.’

‘So she was overweight?’ Duncan asked.

‘I’d say so, yes.’

Brody’s forehead was furrowed. ‘I don’t see where what she was wearing comes in.’

‘Because as the fat melts, it soaks into the clothes. They act like a candle wick, letting the body burn for much longer than it would otherwise. Particularly if they’re made from a flammable fabric.’

Brody still looked shaken. ‘Christ. That’s a hell of an image.’

‘I know, but it’s what happens. Most cases of so-called spontaneous human combustion happen to people who are elderly or drunk. There’s nothing suspicious or paranormal about it. They just drop a cigarette on themselves, or brush too close to a fire and set themselves alight, and are either asleep or incapable of putting out the flames. Like Mary Reeser,’ I said to Duncan. ‘She’s the classic case that’s always cited as being “inexplicable”. But she was elderly, overweight, and a smoker. According to the police report, the last person to see her was her son. She’d just taken sleeping tablets, and was sitting in the armchair in her nightgown-both of which would have acted as wicks-smoking a cigarette.’

Duncan pondered that for a moment. ‘Aye, but why wasn’t anything else damaged by the fire? And why didn’t all the body burn up?’

‘Because even when there’s a lot of body fat to act as fuel, human tissue doesn’t burn particularly hotly. You get a slow-burning fire that’s intense enough to consume the body, but not ignite anything else. Again, think of a candle-it melts as the wick burns, but doesn’t damage whatever’s nearby. As for why the hands and feet sometimes survive…’

I held out my hand, pulling back my sleeve to expose my wrist.

‘They’re mainly skin and bone. There’s hardly any fat on them. And they’re generally not covered by fabric like the torso, so there’s nothing to act as a wick. Hands sometimes get burned just because they’re near the body, unless the arms are outflung. But the feet and sometimes the shins are often far enough removed from the fire to survive. Like they were here. She was lying on one hand, so it got burned along with the rest. But the other hand, and her feet, survived.’

Brody rubbed his chin thoughtfully, hand rasping on the whiskers that were already showing through. ‘You think this “wick effect” was intentional? That somebody did it deliberately?’

‘I doubt it. It’s not something you can easily stage. I’ve never even heard of it happening in a murder before. All the recorded incidents have been with accidental deaths, which was another reason I was slow to chalk this one up as suspicious. No, I think whoever did this probably just wanted to destroy any incriminating evidence they might have left on the body. I’d guess he used a small amount of petrol or some other accelerant to start the fire-not much or the ceiling in the cottage would have been more scorched than it was-then dropped a match on to the body and got out.’

The furrows on Brody’s forehead had deepened. ‘Why didn’t the killer torch the entire cottage?’

‘I’ve no idea. Perhaps he was worried that might attract too much attention. Or he hoped it would look more like an accident this way.’

They were silent as they considered that. Finally Duncan spoke.

‘Was she dead?’

I’d spent time wondering about that myself. There had been no sign that the woman had moved around after she was set on fire, no evidence of her trying to put out the flames. The blow that had cracked her skull would at the very least have left her unconscious, and perhaps even comatose. But dead?

‘I don’t know,’ I said.

The walls of the clinic shook under the gale’s onslaught. Somehow the sound seemed only to heighten the silence after they’d gone. I pulled on one of my last remaining pairs of surgical gloves. There was an almost full box of them in one of the cupboards, but I didn’t want to use them unless I had to. Cameron was tetchy enough without my helping myself to his supplies.