A rare case of serial killing by poisoning.

A case of serial killing by poisoning by a 59-year-old practical nurse is discussed. Following a report by an emergency-room doctor of an attempted murder, police performed an investigation into all deaths of patients in the nurse's care. Earlier, a medico-legal cause-of-death investigation had been performed on two of these cadavers, but in the other three cases the death certificate had been issued after a medical investigation only. In two of these latter cases, the body had been cremated, but fixed histological samples taken at medical autopsy were available, while in one case the person had died recently and the body was thereafter exhumed and autopsied. All of the suspected victims were older people who required nursing, and the nurse's course of action was consistent in all cases. In the absence of ordinary post-mortem toxicology samples in the medical cases, extraordinary evidence--paraffin-embedded liver tissue samples originally taken for histology at autopsy--was successfully recovered in two cases and analyzed for drugs. In all five cases, drugs not prescribed to the patient were detected, including digoxin, dixyrazine, citalopram, venlafaxine, and benzodiazepines (diazepam, chlordiazepoxide, temazepam, and oxazepam). The nurse was eventually found guilty of five murders by poisoning, five attempted murders, and three aggravated assaults. The nurse was sentenced to life imprisonment.