Krahe is widely reputed to have been corrupt, and is often referred to as having been one of the most feared New South Wales Police officers of his day. He was a close associate of other allegedly corrupt New South Wales police officers, including the notorious detectives Roger Rogerson, Donald Fergusson, Ray Kelly, and former New South Wales Police Commissioner Frederick Hanson. He also mentored detective Murray Riley who became a notorious drug smuggler. Krahe is alleged to have had a long-standing corrupt relationship with powerful criminal Lenny McPherson, who was known as the "Mr Big" of Sydney organised crime, also running with a notorious gang called the Toecutters. Members of the group included Kevin Gore, William Donnelly, Linus Driscoll, Frank "Baldy" Blair , Jake Maloney, and John "Magician" Regan. Krahe joined the force in 1940, and served until retirement at the rank of detective sergeant in 1972.