A Police Forensic Identification Services vehicle on scene while authorities comb through an apartment in Toronto in connection with the investigation of an alleged serial killer.
Richard Lautens/Toronto Star via Getty Images
German police say they have evidence that former nurse Niels Högel murdered at least 84 people. He was already convicted in 2015 of two other murders. Above, Högel covers his face with a folder next to his lawyer in German regional court in 2014.
Ingo Wagner/AFP/Getty Images
Donald Harvey is led back to jail in 1987 after pleading guilty to eight murder charges and one voluntary manslaughter charge in London, Ky. He was serving consecutive life sentences when he died Thursday at age 64.