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.