"Pick your poison" may be the old saying, but most poisoning victims don't get to pick their poison--someone else does it for them. Arsenic, cyanide, and strychnine are the things we think of immediately as poisons. Most pesticides are poisonous to humans, as are the materials sold as rat or rodent poisons. Probably the most famous character in history to die from poison was Socrates, who drank tea made from the hemlock plant. This plant, which resembles parsley, contains a variety of highly toxic chemicals. The most potent of these is coniine, a neurotoxin that destroys the functioning of the central nervous system.
The list of potentially poisonous substance is very large. Many poisons act slowly or require a large dose to be lethal. Poisoning cases can be accidental or suicides, while other poisoning cases are clearly homicides. Many poisons are neurotoxins, affecting the nervous system in a variety of ways but generally leading to impairment of lung function and suffocation of the victim. Homicide poisoning is often intended to mimic some medical situation, a heart attack or diabetic coma. This makes determining the cause of death difficult. However, the forensic toxicologist, like any other forensic investigator, has a broad base of knowledge and a wide array of chemical analytical methods available to dissect even the most complex poison cases.
Murder Most Foul
That's how the news media portrayed the murder of Nevada Sate Controller Kathy Augustine by her third husband, Chaz Higgs. Police believed that Higgs gave her a lethal dose of the muscle relaxant succinylcholine. Higgs was the nurse who had cared for Charles Augustine, her second husband, after his stroke. Shortly after Charles's death, Higgs married Kathy Augustine. At the time she died, she was running for State Treasurer. However, Augustine had been impeached by the Nevada Assembly for misuse of state funds. Higgs, who apparently married her because he thought she would have money and power, decided to murder her.
Being a nurse, Higgs had access to a wide array of drugs. The choice of succinylcholine was a good one because it is not normally tested for in toxicology screens. Succinylcholine is a strong muscle relaxant that paralyzes the respiratory muscles. It is normally used in a hospital to allow the insertion of a breathing tube into the throat of a patient who is still conscious. In higher doses it can paralyze the entire breathing apparatus, and the victim slowly suffocates to death. The autopsy showed that Augustine had died of a heart attack. A small needle mark on her buttocks was overlooked in the initial autopsy. However, investigators were not so sure, and when police searched Higgs' house they found succinylcholine and other drugs in his possession. Higgs was arrested and eventually convicted of her murder.
From Russia with Love
In November 2006, ex-Russian spy Alexander Litvinenko was fatally poisoned with Polonium-210, a highly radioactive material. He survived for several days and suffered greatly during the time. Areas of the hotel where litvinenko stayed and a sushi restaurant that he frequently visited also showed high levels of radioactivity. He would have to ingest a relatively large amount of Polonium-210 to cause fatal poisoning. The material could have been placed in his food on several occasions. However, Scotland Yard officials are not sure how the radioactive material actually entered his body. It is the first time that a radioactive agent has been used as a poison in the UK.
In 1986, an autopsy performed in Japan by Dr. Ono Yokichi led to no clear cause of death, until a toxicology search revealed small amounts of an alkaloid toxin, aconite. Aconite is a plant indigenous to many parts of the world. All parts of this plant are poisonous, but the root is the most highly toxic. A half tablespoon of a tincture of aconite root placed in a bottle of whisky is enough to kill a very large man. A tincture is an alcohol extract of the material. Placed in a drink, the alcohol goes unnoticed. Aconite has been called "the perfect poison to mask a murder." It can be detected only by sophisticated toxicology analysis using equipment that is not always available to local forensic labs. In some poorer cultures is called the "Queen of Poisons."