When one hears the words homicidal poisoning, the first thing that comes to mind is often the sweet, misguided aunts of Mortimer Brewster and his wife Elaine Harper in the comedy "Arsenic and Old Lace."
Calling it one of their "charities," the aunts explain to Mortimer that they end the presumed suffering of lonely old bachelors by serving them elderberry wine spiked with arsenic, strychnine and "just a pinch of cyanide."
In real life, homicidal poisoning is anything but funny and usually not committed by someone people refer to as "sweet." The perpetrators carry out these sinister crimes through cunning and careful planning. Their subterfuge deceives their victims who unknowingly ingest poisons and suffer dire, and often lethal, consequences.
But how does an investigator know when a victim's death is due to premeditated poisoning as opposed to suicide or accidental ingestion? The savvy detective familiarizes himself with the signs of accidental poisoning, signs of possible toxins and the forensic tests used to prove homicidal poisoning took place.
Poisonings' fatal attraction
The terminally ill, mentally incapacitated, drug addicts, the elderly and the very young are at highest risk of poisoning. The other high-risk group is the unwanted spouse or lover. The offender is usually personally involved with the victim and is often in the role of caregiver. Poisoners often position themselves as an individual trying to "nurse" the victim back to health.
Why do they do it? Poisoners often derive pleasure from seeing their victims suffer, frequently staying to watch their target experience the poison's effects. The thrill of the poisoner's power over the victim is what motivates the perpetrator to serially offend.
There are of course other motivations for homicidal poisoning. There is a syndrome called Munchausen Syndrome by Proxy. In the actual syndrome called Munchausen Syndrome, a person may harm themselves to gain attention from family and medical personnel. In Munchausen Syndrome by Proxy, the harm is done to others, usually children. There are documented cases of mothers poisoning their children in order to attract attention and sympathy from others.
Today, perpetrators of homicidal poisonings are often employed in the medical or caregiving fields. Though there are no proven theories to explain this phenomena, perhaps their behavior is similar to that of pedophiles, who often take on roles in positions of trust over children, such as coaches, clergy and other professions, in order to gain access to their victims. Poisoners, in some cases, take on jobs that give them access to poisonous substances, and having poisons (drugs) in ready reach and extensive knowledge of their effects may be what tempts perpetrators to use them in a crime.
The authors of a 2004 FBI study on homicidal poisonings were unable to find much information on the personality traits of people who use poison to kill. They did speculate, however, that a large number of poisonings go undetected.
A poison for all tastes
There are many definitions of what is a poison. Some classifications break poisons down into the category of vegetable, mineral or synthetic. Others categorize poisons as organic or inorganic. Some simply describe poisons as any substance that can cause harm to life. Basically, this definition covers everything. However, it is the substances that can be lethal in small amounts that are most easily used in homicidal poisonings. This helps narrow the possibilities somewhat.
The ideal poison for committing a homicide must be: odorless, tasteless, difficult to detect and mimic the symptoms of naturally occurring diseases, finds Anil Aggrawal, professor of Forensic Medicine at the Maulana Azad Medical College in New Delhi, India.