Toronto hospital baby deaths

The Toronto hospital baby deaths, believed to be homicides, occurred in the Cardiac ward of the Hospital for Sick Children between July 1980 and March 1981. They ended when the police were called in and the digitalis-type medication used for the killings (digoxin) began to be kept under lock and key. Three nurses were at the centre of the investigation, and an apparent attempt to poison nurses' food. One of the nurses, Susan Nelles, was charged with four murders, but the prosecution was dismissed a year later on the grounds that she could not have been responsible for a death not included in the indictment, which the judge deemed a murder.
A conspiracy between multiple nurses was regarded by the judge as not credible. The lead detective resigned. An official government inquiry discounted claims by the hospital's own former chief of pediatrics that the deaths were not homicides and not proven to be due to digoxin. A second suspect was not prosecuted. The case is officially one of unsolved murders.
Deaths.
The cardiac ward of the Hospital for Sick Children began what was subsequently found to be a several-fold increase in mortality in 30 June 1980. Within two months twenty patient deaths led to a group of nurses approaching the unit's cardiologists, but they kept investigation limited and in-house to prevent a "morale problem". The excess deaths continued but it was not until March 1981 that a bereaved father's extreme distress led to the coroner being brought in and detecting suspiciously high levels of a heart regulating medication digoxin, a powerful form of digitalis, in a dead baby.
Eight days later, he was told that an autopsy by the hospital had already found 13 times the normal concentration of the same heart drug in another dead baby. The medication had not been subject to any security measures. Police were called in and began to search staff lockers when another baby died from digoxin poisoning on 22 March 1981. Examination of work logs and other nurses' subjective impression that a colleague had inappropriate reactions to the deaths led to the arrest and charging with murder of a nurse, who was released on bail.
In January 1982, babies became ill in a separate department, it was later found epinephrine, which was not supposed to be on that ward, had somehow been substituted for vitamin E, there had been non-fatal unauthorized digoxin administration to other babies, and another death was, contrary to what the hospital said at the time, caused by unauthorized administration of digoxin. In September 1981, team leader nurse Phyllis Trayner (died 2011) found heart drug capsules in food she was eating and another nurse found the capsules in her soup.
Police investigation and inquiry.
Susan Nelles was arrested and charged with murder, but a judge acquitted her at the preliminary hearing stage and the case never went to trial, partly because she had not been on duty when one death the judge decided was an additional murder occurred, and more than one nurse being involved in a series of motiveless murders strained credulity. The exonerated nurse did not believe that there had been any murders, and in a 2011 interview she reiterated that the 1985 inquiry report had been incorrect in stating that many deaths during a rise in mortality on the ward (from one a week to five) had been deliberate homicides. Data from the investigation was sent to the US Centers for Disease Control and Prevention, which discovered that Traynor was the only person who had been on duty for all 29 cases of death being looked at. In 1984 two nurses testified they had seen Traynor making a 21 March 1981 unauthorized injection into the IV of a baby who died three hours later. A commission of inquiry listed eight of the baby deaths as murder, with another 13 as highly suspicious. Later reports mention a total of thirty-two babies and three children.
Traynor, who denied any impropriety in her behaviour on the ward, was questioned in televised inquiry hearings, and resigned after the inquiry's report was published. Although chemical interaction between digoxin and rubber tubing used in its administration was used to question whether the deaths were the result of foul play, the case is officially listed as one of unsolved murders.