‘Yes, well, he is stable. But his condition is not good, I must tell you. The substance he ingested was arsenic.’

Rachel’s face filled with dismay. Sachs put her arm around the woman.

Arsenic was an element, a metalloid, which meant it had characteristics of metals and non-metals, like antimony and boron. And it was, of course, extremely toxic. Rhyme reflected that the unsub had moved beyond plant-based toxins to a different category altogether – elemental poisons were no more dangerous but they were easier to come by since they had commercial uses and could simply be purchased in lethal strengths; you didn’t need to extract and concentrate them.

‘I see there are police here.’ Now he glanced at the wheelchair with more understanding. ‘Ah, I’ve heard about you. You are Mr Rhymes.’

‘Rhyme.’

‘And I know Mr Sellitto is a police officer too. You gave me the information about the possible poisons?’

‘That’s right,’ Sachs said.

‘Thank you for that but we determined arsenic quickly. Now, I must tell you. His condition is critical. The dose of the substance was high. The organs affected are the lungs, kidneys, liver and skin and he’s already had changes in fingernail pigmentation known as leukonychia striata. That is not a good sign.’

‘Inorganic arsenite?’ Rhyme asked.

‘Yes.’

Arsenic (III) is the most dangerous of all types of the toxin. Rhyme was quite familiar with the toxin. He’d run two cases in which it had been used as a murder weapon – in both cases spouses (one husband, one wife) had dispatched their partners with the substance.

Three other cases he’d run of suspected arsenic poisoning had turned out to be accidental. The toxin occurs naturally in groundwater, particularly where fracking – high-pressure geologic fracturing to extract oil and gas – has occurred.

In fact, throughout history, for every intentional victim of arsenic poisoning – like Francesco I de’ Medici, Grand Duke of Tuscany – there were many more accidental victims: Napoleon Bonaparte, possibly done in by the wallpaper of the rooms to which he’d been exiled on St Helena; Simón Bolívar (the water in South America); and the American ambassador to Italy in the 1950s (flaking paint in her residence). It was also possible that the madness of King George was due to the metalloid.

‘Can we see him?’ Sachs asked.

‘I’m afraid not. He’s unconscious. But a nurse will call you when he comes to.’

Rhyme noted and, for Rachel’s sake, appreciated the conjunction.

When, not if.

The doctor shook hands. ‘You believe someone actually did this intentionally?’

‘That’s right.’

‘Oh, my.’

His mobile rang and without a word he turned away to answer.

CHAPTER 44

In October 1818 an attractive woman with an angular face and piercing eyes died at the age of thirty-four in Spencer County, Indiana.