Donald Harvey, a health care worker called the Angel of Death by the news media after he killed dozens of hospital patients under his care in the 1970s and ’80s, died on Thursday after he was attacked in his prison cell in Ohio. He was 64. Mr. Harvey showed no remorse for his actions during his 1987 trial in Ohio. During his trial and throughout the years of his incarcerations, he held firm in his belief that he had done his victims a favor.