Stephen Booth - Dying to Sin

‘Potassium nitrate is an explosive, then?’ said Fry.`

‘Not on its own. It does have another useful property, though, particularly for fireworks manufacturers. A mixture of potassium nitrate and sugar produces a smoke cloud six hundred times its own volume. Just great for smoke bombs.’

‘How does it kill tree stumps?’

‘It doesn’t really kill them. You have to kill the stump first — then the potassium nitrate makes it decompose faster.’

‘Wait a minute,’ said Cooper. ‘Those compost heaps — did you say they were called “nitre beds”?’

‘That’s right. One of the common non-scientific names for potassium nitrate is — ’

‘- saltpetre?’

‘Correct.’

Cooper found that he wasn’t in the least surprised. It seemed to fit so naturally with what he’d learned already of the owners of Pity Wood Farm, and the other residents of Rakedale.

‘Potassium nitrate is used in Edgar Allan Poe’s story “The Cask of Amontillado” as the lining of the crypt where Montresor buries Fortunato alive. It’s why he has so much trouble with his breathing in his last moments. “ For the love of God, Montresor! ”’

‘Didn’t the IRA use saltpetre in their bomb-making operations at one time?’ said Fry. ‘I had a feeling it had been put on a restricted list, not available for sale to the general public.’

Hitchens laughed. ‘You can make bombs from sugar and fertilizer, so why would anyone worry about saltpetre?’

‘Also, it’s been implicated in having carcinogenic properties.’

‘I don’t think anyone was worrying about getting cancer or making bombs,’ said Cooper.

‘Oh?’

‘This other stuff in the kitchen. Did it include sesame seeds, by any chance?’

‘Yes, it did,’ said Hitchens. ‘How on earth did you know that, Ben?’

He’d have to ask Amy for the exact wording, but Cooper thought he could remember the recipe pretty well.

Squeeze out the blood. Embalm it in a shroud and steep it in a solution of saltpetre, salt and pepper for two weeks, then dry in the sun. The candles are made from a hanged man’s fat, wax and Lapland sesame .

‘I’d like to make a prediction,’ he said. ‘I predict that if we find another body at Pity Wood Farm, it will be missing a hand.’

Within a few minutes, and thanks to the internet, Cooper knew how to make potassium nitrate himself. The practical part was simple. You could either dissolve solid fertilizer in boiling water, or boil down a liquid fertilizer until crystals started to form. When the solution had cooled to room temperature, it was placed in a fridge. The white crystalline precipitate was mainly KNO 3. Garden products tended to contain ammonium nitrate, too, which contaminated the KNO 3.

‘We should have picked this up earlier,’ said Hitchens. ‘Potassium nitrate can cause eye and skin irritations. Breathing it in can irritate the nose and throat, causing sneezing and coughing. High levels can interfere with the ability of the blood to carry oxygen, causing headaches, fatigue, dizziness and a blue colour to the skin and lips. Even higher levels can cause trouble breathing, collapse and death. Long term, potassium nitrate may affect the kidneys and cause anaemia. Chronic long-term health effects can occur some time after exposure and can last for months or years.’

‘Is this really something you ought to keep in your fridge?’ asked Murfin.

‘No, Gavin.’

‘And what was it that Derek Sutton died from, did you say?’

‘Heart failure.’

‘That appears on so many death certificates. It’s what doctors write in when they can’t see any other cause of death but don’t want to put the family through the ordeal of a postmortem.’

‘Obviously, no one would have suspected potassium nitrate poisoning at the time, so there wouldn’t have been any toxicology done, even if there had been a PM,’ said Fry.

‘Well, it’s academic, since there wasn’t a postmortem,’ said Hitchens. ‘Derek Sutton was signed off, certificated and cremated within a week.’

‘It would be cremation, of course. So no chance of getting an exhumation order.’

‘You say that no one would have suspected potassium nitrate poisoning,’ said Cooper. ‘But his brother Raymond might have suspected it, if he knew what Derek was up to.’

Hitchens shook his head. ‘That old man? How would he have known the effects of potassium nitrate? Who knows what saltpetre is exactly? I didn’t, until just now.’

‘Even so, he must have wondered what was wrong. You don’t just drop suddenly without any other symptoms, do you?’

Hitchens checked the report. ‘Eye and skin irritations, sneezing and coughing, headaches, fatigue, dizziness, a blue colour to the skin and lips, trouble breathing.’

‘I found several sites on the internet where I could order food-grade saltpetre. Lots more where it’s listed as an ingredient in garden chemicals.’

‘OK.’

He’d also found a method for treating skin infections that had supposedly been passed from father to son over many generations in farming. If you got bitten or scratched and it looked as though the wound was getting infected, you should bathe the area in a solution of hot water and saltpetre. It inhibited the growth of organisms associated with skin infections. Clostridium, Streptococcus and Staphylococcus. It made sense. He was just surprised that he’d never heard of it in his own family. Father to son over generations? Maybe Matt used the treatment on the quiet.

‘Ben — this thing about a hand of glory,’ said Fry, interrupting his reading. ‘You don’t think you’re letting the superstition business get to you too much?’

‘Not me. I think it had got to Derek Sutton, though.’

‘You really think there’s a body without a hand somewhere?’

‘Yes.’

‘Prepared to bet on it?’

‘I’m not really a betting man,’ said Cooper.

‘Ha-ha.’

Potassium nitrate had a smell reminiscent of burnt gunpowder. That rang a bell with Cooper. For a while, supplies of fertilizer had been stored in a breeze-block extension to the main barn at Bridge End. The inside always had a heavy smell of potassium nitrate fertilizer. Burnt gunpowder was right — it had always made him think of Bonfire Night and firework displays.

He would probably never be able to go to a garden centre without being reminded of it these days. Not without being reminded of poor Derek Sutton, preparing his saltpetre recipe in the kitchen at Pity Wood.

Fry was seething quietly at her desk when Hitchens appeared at her side, his face creased with discomfort.

‘Diane, have you got a minute?’

‘Sir?’ said Fry, automatically responding to the tone of his voice. It was a management tone, the kind of voice people used when you were being summoned into their office for a reprimand. Or to get bad news. ‘Is something wrong?’

‘Let’s just step into my office, shall we?’

They moved out of earshot of the team in the CID room and Hitchens shut the door of his office with a deliberate slam.

‘I shouldn’t be telling you this,’ he said. ‘But we’ve worked together for a while now, and I think you ought to know as soon as possible. Sit down, won’t you?’

Reluctantly, Fry sat. She preferred to stay on her feet when they were discussing an enquiry. Sitting in the chair across from his desk felt too much like a disciplinary interview, the recalcitrant pupil called to the headmaster’s room.

‘There was a meeting of the CID management team this morning,’ he said.

Fry nodded. Of course, everyone knew that. Word had gone round the CID room like the wind. DIs and above were in a meeting with the new superintendent. Something was afoot, they said. Changes were going to be made. The End of the World was nigh.