Proving Poisoning

Part of the Forensic Science and Medicine book series (FSM)


The following elements are key to proving that someone has been poisoned:
  • Discovery: This consists of legally proving that a crime was committed, and demonstrating beyond reasonable doubt that death was caused by poison, administered with malicious or evil intent to the deceased. Never forget the importance of the chain of evidence on all investigational specimens.

  • Motive: This is critical because the investigator must clearly establish the instigating force behind the action. Why would anyone want to carry out such an act on the victim? This is where the close study of the victim (victimology) becomes central to the case.

  • Intent: This constitutes the purpose or aim that an individual would have in commission of the act. Here the investigator will cover the desired outcome of the criminal act.

  • Access to the poison responsible for the death: The criminal investigator must present such evidence as proof of sale of the poison, with such things as receipts or the signature on a poison register at the point of sale. Is there any original packaging, wrappers, or containers associated with the suspect? It may suffice to prove that a suspect has had access at a workplace, used toxins or poisons in his or her occupation, or had a hobby that involved the use of the poison in question.

  • Access to the victim: Is there any proof that a suspect has knowledge of the victim’s daily habits, could have had the opportunity to overcome any of the victim’s normal defenses, and was able to administer the poison either directly or indirectly?

  • Death caused by poison: There must be sufficient, sound evidence that would induce a reasonable person to come to this conclusion. Remember that in order to prove death by poison, the presence of the poison in the systemic circulation and/ or body organs must be proven. The presence of the poison only in the gastrointestinal (GI) tract does not prove death by poisoning. The GI tract from the mouth to the anus is much like a garden hose, hollow and open at both ends, and therefore outside the topological framework of the body. Consequently, to have met its fatal potential, the poisonous compound must have been absorbed through the walls of the gut and entered the body’s systemic circulation so that it could get to the site that caused the untoward effect.

  • Death homicidal: This cannot be proven analytically or by autopsy but depends on the work of the criminal investigator at the crime scene, and examination of witnesses. This proof must categorically eliminate the possibility that the death resulted from an accident, intentional substance abuse, or an act of suicide.


Uniform Crime Report Poisoning Case Poison Register White Victim Garden Hose 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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  1. Doyle AC: A scandal in Bohemia. In: The Complete Sherlock Holmes. Doubleday & Co., Garden City, NY, 1930, p. 163, Westveer AE, Jarvis JP, Jenson CJ: Homicidal poisoning—the silent offense. FBI Law Enforcement Bull, August 2004:1-8.Google Scholar
  2. Westveer AE, Trestrail JH, Pinizzoto J: Homicidal poisonings in the United States—an analysis of the Uniform Crime Reports from 1980 through 1989. Am J Forensic Med Pathol 1996;17(4):282–288.PubMedCrossRefGoogle Scholar
  3. Westveer AE, Jarvis JP, Jensen CJ: Homicidal poisoning—the silent offense. FBI Law Enforcement Bill. August 2004: 1–8.Google Scholar

Suggested Reading

  1. Browne GL, Stewart CG: Reports of Trials for murder by poisoning. Stevens and Sons, London, 1883.Google Scholar

Copyright information

© Humana Press Inc. 2007

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