'Angel of Death' serial killer Donald Harvey dies after jail cell beating

A serial killer who pleaded guilty to 37 murders has died after he was badly beaten in his jail cell.

Donald Harvey became known as the Angel of Death after poisoning patients and letting their oxygen run out while working in hospitals in Cincinnati, Ohio, and in London, Kentucky.

He escaped the death penalty by entering into a plea deal and had been serving an 80-year minimum sentence.

His first parole hearing was due in 2043.

The 64-year-old was found beaten in his Toledo prison cell two days ago and authorities have now confirmed his death.

Working as a nurse's assistant, Harvey said he had killed his victims to end their suffering as many were chronically ill.

He used arsenic and cyanide to poison most of them, often slipping it into food. Others died when he let their oxygen tanks run out.

Harvey was caught when a medical examiner smelled a faint trace of almonds - the telltale sign of cyanide - during a post-mortem.

After being convicted, he claimed his was behind another 18 patient deaths at the Veterans Administration Medical Center in Cincinnati.

He told a newspaper that he liked having control of who lived and who died.

Former Hamilton County Prosecutor Arthur Ney Jr, who took charge of the cases in Cincinnati, said Harvey was not a mercy killer.

"He killed because he liked to kill," Mr Ney said.