Robert Morgenthau, who served for 35 years as Manhattan district attorney, died Sunday at 99, The New York Times reports. Born to a wealthy family in 1919, Morgenthau served for almost nine years as U.S. attorney for the Southern District of New York before being elected as Manhattan DA in 1975. He estimated that he supervised 3.5 million cases in that time, the Times reports, including the prosecution of “preppy killer” Robert Chambers and John Lennon assassin Mark David Chapman.