The hospitals staff soon began to notice a disappearance of narcotics. They compared the clinics duty record against the dates that the drugs had been removed and concluded that Letter had been stealing them. When doctors first suspected that something sinister was going on, the bodies of 42 patients were exhumed from their graves, all of whom had died during Letters shifts. A total of 80 deaths took place during the nurses shifts, but 38 were unable to be examined because they had been cremated. The investigation revealed that Letter was fatally injecting patients with a cocktail of tranquilizers and muscle relaxants. He was arrested in July 2004 and admitted that he killed 12 patients by lethal injection, but that he could not remember any more. Most of his victims were at least in their 70s, so their deaths were at first overlooked. Letter claimed that he was administering lethal injections to his patients because he felt sorry for them. He wanted to liberate their souls, said Letters lawyer, Wilhelm van Eckert. For him, his patients were trapped in their sick bodies. However, 2 women who were in their 40s were given the lethal injections, and at least 6 patients were in no danger of dying. A few had even died soon after being admitted to the hospital but before being fully examined.