QIn today’s age of high-tech forensics, do poisons still work for fictional murders?
GB
AYes, people often get away with poisoning because it is not thought of. If an eighty-five-year-old demented person with heart and lung disease dies in his sleep in a nursing home, his private MD might sign the death certificate as a natural cardiac death, and the ME would accept it. Likely no autopsy would be done and no expensive toxicological exams would be undertaken, so an overdose of morphine or digitalis or whatever could go undetected. But if a five-million-dollar inheritance was in play and if the insurance company didn’t have to pay for a victim of murder or if one family member suspected another, the ME might be asked to open a file and investigate.
The first step in getting away with a poisoning murder is to make it look like something else. Keep the ME completely out of the picture or at least give him an easy answer for the cause of death. If no murder is suspected, he’ll take the path of least resistance, which is also the cheapest route. The ME must live with and justify his ever-declining budget. If he is wasteful, he’ll be looking for a job. So give him a cheap and easy out.
The second step is to use a poison that is not readily detectable and will slip through most drug screens. Drug screens on both the living and the dead typically test for alcohol, narcotics, sedatives, marijuana, cocaine, amphetamines, and aspirin. Some screen for a few other classes. Once a member of a class is identified, further testing to determine exactly which member of the class is present and in what amount will follow. These tests are more expensive and time consuming, but if the screen shows something it will be pursued. If not, to save money the death is attributed to something else and life goes on. Remember that a common cause of death in middle-aged folks is a cardiac arrhythmia without a heart attack. There are no autopsy findings in such deaths. A heart attack can be seen but not an arrhythmia since it is purely electrical.
That said, if a poison is suspected and if the funds and interest to pursue it are present, virtually anything can be found in an intact corpse. Using gas chromatography in conjunction with either mass spectrometry (GS/MS) or infrared spectroscopy (GC/IR) will give a chemical fingerprint for any molecule. Because each molecule has its own structure and thus its own fingerprint, every compound can be distinguished from every other one.
For these reasons, poisons are still rich tools for the writer of crime fiction.