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Pontifications on Poison

Being some ramblings on events associated with poisonous plants.

Monday 28th November 2011

I shall have to rethink parts of one of my talks after stumbling across a paper suggesting that a couple of things I’ve been including in my ‘Medical Murderers’ presentation are not as clear cut as I thought.

The stumbling started when I happened upon a 1999 paper by two French toxicologists who reviewed cases of human poisoning due to plant extracts before looking at a new method of determining the concentration of plant poisons post mortem.

I followed one of their references, a 1996 paper entitled ‘Toxicity following accidental ingestion of Aconitum containing Chinese remedy’ (the abstract is here), and during a further search to see if I could find the full paper found, instead, a 2006 paper entitled ‘Aconitine involvement in an unusual homicide case’ (available in full here).

Aconitum napellus, monkshood

Aconitum napellus, monkshood

It describes a case from Belgium where a woman used Aconitum napellus, monkshood, to murder her husband. The case began when a car was discovered with its front in a ditch next to a road. The driver was dead behind the wheel. The appearance that this was a simple car accident either caused by the driver collapsing at the wheel or caused some other way but killing the driver on impact was soon shown not to be the case when a crude, partially burnt fuse was found hanging from the fuel tank. Closer examination of the body revealed signs of asphyxia, strangulation and frequent blunt force trauma to various parts of the body.

The police investigation into the circumstances of the man’s death made no progress for five years but, then, DNA testing was conducted that implicated the man’s wife. When questioned she confessed to his murder at their home some 100km from the crash site.

The woman had boiled up the leaves and stalks of three Aconitum napellus plants and added the liquid obtained, together with prescribed sleeping tablets, to a bottle of red wine. The woman said her husband showed no symptoms of poisoning so she went to bed. Three and a half hours later she found him dead in a chair. For some reason, she decided to move the body upstairs, using ropes and a roll of carpet before deciding to dispose of it and bringing it back downstairs and out to the car. This trip up and down the stairs explained the many bruises found on the body.

She positioned it in the driver’s seat and then sat on the dead man’s lap as she drove the 100km to the place where she drove the car into the ditch and then tried, unsuccessfully, to set fire to it. She then took a taxi home.

It does seem a little strange that the case took so long to solve. And here’s where we start to get into the changes I’ll need to make to my talk. The underlying theme is the development of forensic science. The notion that, two hundred years ago, we were only just beginning to identify the alkaloids that make poisonous plants toxic and we had almost no tools to identify them if used to effect a poisoning but, today, our science is so sophisticated and so mature that there is no chance of a poison going undetected.

But, although these chemicals can be identified the important first step is to look for them. In this Belgian case, the only tests conducted, at first, were to establish how much the deceased had been drinking and if he had used drugs. Once the wife had confessed, toxicologists were able to establish the presence of the alkaloids of monkshood, aconitine and its relatives, but we’ll never know if they would have found them if they didn’t know what they were looking for.

I usually say that Aconitum napellus is not a useful murder weapon because it has a unique taste that will make people aware that something about their food or drink is not right. But, in this case, the victim seems to have happily drunk the bottle of red wine without comment. So that’s something else I’ll have to modify in my presentation.

My key line, that getting away with murder is about no-one realising murder has occurred, also needs some modification. Clearly, in this case, foul play was suspected but the wife came very close to getting away with it. Again, we’ll never know if the police would have been able to make a convincing case against her had she not confessed. So, getting away with murder may just be a matter of hoping that the investigation of your crime is not thorough.