A former nurse in east Texas was sentenced to death Wednesday for the murders of four patients. William Davis, 37, was found guilty last week of killing John Lafferty, Ronald Clark, Christopher Greenaway, and Joseph Kalina. Davis would inject air into patients’ arteries in order to extend their stays in the intensive care unit where he worked so that they would grow sicker and he could make more money by working, he told his wife on the phone. Prior to his arrest in 2018, he also viewed an article titled “List of serial killers by number of victims.”