Simon Beckett - The Chemistry of Death

Mackenzie paused to let the impact of his words hit home. 'Now, I'd say that was something we'd need to know, wouldn't you, Dr Hunter?'

Sally Palmer's house had been transformed since the last time I'd seen it. Then it had been silent and empty; now it was host to grim-faced and uninvited visitors. The courtyard had filled with police vehicles, while uniformed and white-boiler-suited forensics officers went about their business. But the activity only seemed to underline the atmosphere of abandonment, transforming what had once been a home into a pathetic time capsule of the recent past, to be picked apart and pored over.

There seemed nothing left of Sally's presence as I walked across the courtyard with Mackenzie.

'The vet came for the goats,' he told me. 'Half of them were already dead, and he had to destroy a couple of others, but he says it's amazing any survived at all. Another day or two would have finished them. Goats are tough buggers, but he reckoned they must have been a couple of weeks without being fed or watered to get to that state.'

The area at the back of the house where I'd found the dog had been taped off, but other than that it was as I'd found it. No-one was in as much of a hurry to move a dog, and either the forensics team had already finished or felt there were other priorities to examine first. Mackenzie stood back and popped a mint into his mouth as I crouched down beside the body. It looked noticeably smaller than I remembered – not necessarily a trick of memory as by this time the decay would be waging an almost visible war of attrition on what was left.

The fur was misleading, disguising the fact that the dog had largely been reduced to bone. Tendons and cartilage remained, like the open tube revealed by the wound in its throat. But there was hardly any soft tissue left. I used a stick to lightly poke in the earth around it, took in the empty eye sockets, and then stood up.

'Well?' Mackenzie asked.

'It's difficult to say. You've got to take into account the smaller body mass. And its fur will have some effect on the rate of decay. I'm not sure what, exactly. The only comparative work I've done on animals was with pigs, and they have a hide, not a pelt. But I'd guess it'd make it harder for insects to lay their eggs, except in open wounds. So that'll probably slow things down.'

I was talking to myself more than him, rapidly brushing through cobwebs of memory, sifting through the knowledge that had been lying dormant.

'What soft tissue was exposed has had animals picking at it. See this here, around the eye sockets? The bone's been gnawed. Too small for foxes, so it's probably rodents and birds. That probably happened quite early on, because once it gets too ripe they'll leave it alone. But that means less soft tissue, and so less insect activity. And the ground here is much drier than the marsh where you found the woman.' I couldn't quite bring myself to say Sally Palmer. 'That's why it looks dried up. In this heat, without moisture it'll mummify. It changes the way the body decays.'

'So you don't know how long it's been dead?' Mackenzie prompted.

'I don't know anything. I'm just pointing out that there are a lot of variables here. I can tell you what I think, but bear in mind it's only a preliminary estimate. You're not going to get any hard and fast answers just from a quick look.'

'But…?'

'Well, there still aren't any empty pupae husks, but some of these look about ready to hatch. They're darker than those we found around the body, obviously older.' I pointed at the open wound in the dog's throat. On the ground around it, a few shiny black carapaces could be seen crawling in the grass. 'There are a few beetles here as well. Not many, but they tend to come later. Flies and maggots are the first wave, if you like. But as the decay progresses the balance changes. Less maggots, more beetles.'

Mackenzie was frowning. 'Were there beetles where Sally Palmer was found?'

'Not that I saw. But beetles aren't as reliable an indicator as maggots. And, like I say, there are all the other variables to take into account.'

'Look, I'm not asking you to swear under oath. I just want some idea of how long the damn thing's been dead.'

'Rough guess.' I looked at the scrap of fur and bone. 'Twelve to fourteen days.'

He chewed his lip, scowling. 'So it was killed before the woman.'

'That's how it looks to me. Comparing this with what I saw yesterday, the decomposition is perhaps three, four days more advanced. Take off the extra day and night this has been lying outside and you're still looking at around three days. But like I say, it's only guesswork at this stage.'

He eyed me, thoughtfully. 'Do you think you're wrong?'

I hesitated. But he wanted advice, not false modesty. 'No.'

He sighed. 'Shit.'

His mobile rang. He unclipped it from his belt and moved away to answer it. I stayed by the dog's body, scrutinizing it for anything that might cause me to revise my opinion. Nothing did. I bent down to take a closer look at its throat. Cartilage lasted longer than soft tissue, but animals had been here too, chewing the edges. Even so, it was still evident that it was a cut, not a bite. I took a pencil light from my pocket, reminding myself to disinfect it before I examined anyone's tonsils again, and shone it inside. The cut extended all the way to the cervical vertebrae. I played the light on a pale line gouged across the bone. No animal had caused that. The blade had gone so deep it had cut into the spine as well.

That made it a big knife. And a sharp one.

'Seen something?'

I'd been too engrossed to hear Mackenzie return. I told him what I'd found. 'If the bone's marked clearly enough you might be able to tell if the blade was serrated or not. In any event, it would have taken strength to cut that deeply. You're looking for a powerful man.'

Mackenzie nodded, but he seemed distracted. 'Look, I've got to go. Take as long as you like here. I'll tell forensics not to disturb you.'

'No need. I'm done.'

'You won't change your mind?'

'I've told you as much as I can.'

'You could tell us more if you wanted to.'

I was beginning to feel angry at the way he was trying to manipulate me. 'We've already been through this. I've done what you asked.'

Mackenzie seemed to be weighing something up. He squinted into the sun. 'The situation's changed,' he said, reaching a decision. 'Someone else has gone missing. You might know her. Lyn Metcalf.'

The name hit me hard. I remembered seeing her outside the chemist's the evening before. Thinking how happy she'd looked.

'Went running this morning and didn't come back,' Mackenzie went on, relentlessly. 'Could be a false alarm, but right now it doesn't look like it. And if it isn't, if this is the same man, then the shit's really going to hit the fan. Because either Lyn Metcalf's already dead, or she's being held somewhere. And given what was done to Sally Palmer, I wouldn't wish that on anybody.'

I almost asked why he was telling me all this, but even as the question formed I knew the answer. On the one hand he was putting more pressure on me to co-operate; on the other, Mackenzie was simply being a policeman. The fact that I'd reported Sally Palmer as missing had put me low on the list of potential suspects, but if there was now a second victim then everything was up in the air again. No-one could be discounted.

Including me.

Mackenzie had been watching to see how I would react. His expression was unreadable. 'I'll be in touch. And I'm sure I needn't ask you to keep this to yourself, Dr Hunter. I know you're good at keeping secrets.'

With that he turned and walked away, his shadow chasing him across the grass like a black dog at his heels.

If Mackenzie had been serious about my keeping Lyn Metcalf's disappearance to myself he needn't have bothered. Manham was too small a place for something like that to remain secret for long. Word had already spread by the time I'd got back from the farm. It came at roughly the same time as news broke that the murdered woman was Sally Palmer, a double blow that was almost too much to take in. Within hours the mood of the entire village had changed from febrile excitement to one of shock. Most people clung to the hope that the two events would prove unconnected, and that the supposed second 'victim' might yet turn up safe and sound.