Donald Harvey, the nurse's aide dubbed the Angel of Death by the media after killing more than 30 hospital patients under his care during the 1970s and 1980s, died on Thursday (30 March) at the age of 64 after being attacked and beaten in his Ohio prison cell.

Harvey was found injured in his cell two days earlier at the Toledo Correctional Institution, Ohio State Highway Patrol spokesman Lieutenant Robert G Sellers said. Harvey, who was serving multiple life sentences, was beaten by an unnamed inmate in his cell, a patrol report revealed.

One of the most prolific mass murderers in American history, Harvey confessed to killing 37 people, mostly hospital patients, over 20 years in Cincinnati, Ohio and London, Kentucky. He later claimed he murdered 18 others while working at the Veterans' Administration Medical Center in Cincinnati.

According to The Associated Press (AP), Harvey told his former attorney that the murders began in 1970 when he worked at Marymount Hospital in Kentucky. Harvey claimed he was trying to end the suffering of his victims, most of whom were chronically ill patients.

"He killed because he liked to kill"

His protestations were not convincing. Arther Ney Jr, the Ohio prosecutor who handled the case in 1987, told the court. "He is no mercy killer. He killed because he liked to kill."

Harvey used arsenic, cyanide, rat poison or petroleum distillate to poison many of his victims and suffocated patients with their pillows or by allowing their oxygen tanks to run out. He would mix the poison into beverages or foods, the New York Times reported.

Twenty-one of Harvey's victims were patients at the former Drake Memorial Hospital in Cincinnati, where he was a nurse's assistant.

He was caught when a medical examiner smelled cyanide on one of the victims, John Powell, during an autopsy. Not all of his victims were hospital patients. One was his neighbour, a second was his roommate's father, and a third was an acquaintance.

Throughout his trial and his incarceration, Harvey maintained that he had done his victims a favour, The New York Times reported. "I felt what I was doing was right," he said in 1987. "I was putting people out of their misery. I hope if I'm ever sick and full of tubes or on a respirator, someone will come and end it."