can’t imagine our killer risking that happening, not eight times. If they did, they’ll be easy to spot.’
‘ If the injection were subcutaneous,’ I said slowly, ‘or intramuscular, the effect would be delayed.’
‘ By how long?’
‘ I’m not sure in the case of concentrated potassium chloride, but it could be two or three hours.’
‘ Is it easy to get hold of?’
‘ I think you can buy it in a chemist’s. Nothing simpler in a hospital.’
‘ Would it show up on post-mortem?’
I hesitated. ‘I think a large dose would, although the body naturally contains a certain amount.’
‘ So potassium chloride’s a possibility.’ He made a note in his book. ‘What about the nurse who killed those children with insulin?’
‘ Yes,’ I said grimly. ‘In Thatchbury. And she tried all sorts of methods, including potassium chloride as well as suffocation and air embolism. That’s injecting an intravenous bubble of air,’ I added in response to his quizzical look.
‘ So that does actually work, then?’
‘ It’s a bit of an old chestnut really, since you have to inject a hell of a lot, at least a hundred mil. In her case, she didn’t inject enough, and it only made the victim ill.’
‘ So probably not that, then.’ He made another note. ‘You mentioned suffocation — is that really possible?’
‘ Certainly, if the patient’s unconscious. You pinch the nose and put your hand over their mouth.’
‘ But I imagine it would be pretty obvious if you were seen doing it? Which would be quite likely in ITU.’
‘ Yes, and it would also cause the alarm to go off when the heart stopped — if the patient were connected to a monitor.’
‘ That’s a point,’ he said. ‘How many of them were connected to monitors at the time they died?’
We went through the printouts while we finished our sandwiches. Peters hadn’t been on a monitor, of course, nor Mr Thorpe or Mr Goldman, who’d both been transferred to Coronary Care. The others all had, which didn’t tell us very much.
‘ Shall I make some coffee?’ I said, and got up without waiting for an answer.
‘ Let’s get back to insulin,’ Tom said as I handed him a mug a few minutes later. ‘How did they find out that insulin was the agent used in the Thatchbury cases?’
‘ A post-mortem on one of the victims.’
‘ So it’s detectable on PM.’ He made another note. ‘How does it cause heart failure? I only know it as the stuff diabetics use.’
‘ It’s a hormone which controls the amount of sugar released into the blood. Diabetics can’t make it, so they have too much sugar. Conversely, if you have an excess of insulin, the blood’s starved of sugar and that leads to heart failure.’
‘ How long does it take to work? After you’ve injected it.’
‘ It varies. Soluble insulin acts in a minimum of thirty minutes, but it can take up to several hours.’
‘ And if you injected it intramuscularly …?’
‘ It would presumably take longer — I don’t know. But, Tom, the killer wouldn’t have to do that, since there are delayed action forms of insulin.’
He groaned. ‘What are they and how long do they take to work?’
‘ Er — well, there’s insulin zinc, which takes a bit longer, and there’s protamine zinc insulin, or PZI, which takes longer still.’
He was busily scribbling. ‘How much longer?’
‘ I’ll have to look that up when we get back. It’s a long time, though.’
‘ OK. So insulin’s a strong possibility.’ He looked up. ‘Are all these various forms easily available?’
‘ Yes, they’re just kept in a fridge.’
‘ I wonder if these could be copycat killings,’ he mused. ‘Should we be looking for a nurse with a similar sort of personality defect to the one in Thatchbury?’
‘ She had Munchausen’s syndrome, and also Munchausen’s syndrome by proxy.’
‘ Which means?’
‘ In the former, you gain attention by inventing symptoms of illness in yourself; in the
‘ If the injection were subcutaneous,’ I said slowly, ‘or intramuscular, the effect would be delayed.’
‘ By how long?’
‘ I’m not sure in the case of concentrated potassium chloride, but it could be two or three hours.’
‘ Is it easy to get hold of?’
‘ I think you can buy it in a chemist’s. Nothing simpler in a hospital.’
‘ Would it show up on post-mortem?’
I hesitated. ‘I think a large dose would, although the body naturally contains a certain amount.’
‘ So potassium chloride’s a possibility.’ He made a note in his book. ‘What about the nurse who killed those children with insulin?’
‘ Yes,’ I said grimly. ‘In Thatchbury. And she tried all sorts of methods, including potassium chloride as well as suffocation and air embolism. That’s injecting an intravenous bubble of air,’ I added in response to his quizzical look.
‘ So that does actually work, then?’
‘ It’s a bit of an old chestnut really, since you have to inject a hell of a lot, at least a hundred mil. In her case, she didn’t inject enough, and it only made the victim ill.’
‘ So probably not that, then.’ He made another note. ‘You mentioned suffocation — is that really possible?’
‘ Certainly, if the patient’s unconscious. You pinch the nose and put your hand over their mouth.’
‘ But I imagine it would be pretty obvious if you were seen doing it? Which would be quite likely in ITU.’
‘ Yes, and it would also cause the alarm to go off when the heart stopped — if the patient were connected to a monitor.’
‘ That’s a point,’ he said. ‘How many of them were connected to monitors at the time they died?’
We went through the printouts while we finished our sandwiches. Peters hadn’t been on a monitor, of course, nor Mr Thorpe or Mr Goldman, who’d both been transferred to Coronary Care. The others all had, which didn’t tell us very much.
‘ Shall I make some coffee?’ I said, and got up without waiting for an answer.
‘ Let’s get back to insulin,’ Tom said as I handed him a mug a few minutes later. ‘How did they find out that insulin was the agent used in the Thatchbury cases?’
‘ A post-mortem on one of the victims.’
‘ So it’s detectable on PM.’ He made another note. ‘How does it cause heart failure? I only know it as the stuff diabetics use.’
‘ It’s a hormone which controls the amount of sugar released into the blood. Diabetics can’t make it, so they have too much sugar. Conversely, if you have an excess of insulin, the blood’s starved of sugar and that leads to heart failure.’
‘ How long does it take to work? After you’ve injected it.’
‘ It varies. Soluble insulin acts in a minimum of thirty minutes, but it can take up to several hours.’
‘ And if you injected it intramuscularly …?’
‘ It would presumably take longer — I don’t know. But, Tom, the killer wouldn’t have to do that, since there are delayed action forms of insulin.’
He groaned. ‘What are they and how long do they take to work?’
‘ Er — well, there’s insulin zinc, which takes a bit longer, and there’s protamine zinc insulin, or PZI, which takes longer still.’
He was busily scribbling. ‘How much longer?’
‘ I’ll have to look that up when we get back. It’s a long time, though.’
‘ OK. So insulin’s a strong possibility.’ He looked up. ‘Are all these various forms easily available?’
‘ Yes, they’re just kept in a fridge.’
‘ I wonder if these could be copycat killings,’ he mused. ‘Should we be looking for a nurse with a similar sort of personality defect to the one in Thatchbury?’
‘ She had Munchausen’s syndrome, and also Munchausen’s syndrome by proxy.’
‘ Which means?’
‘ In the former, you gain attention by inventing symptoms of illness in yourself; in the
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