How did a seemingly normal young guy turn into an accused serial killer? The Arizona Republic asks that question in the case of Cory Morris, 24, who has been charged with murder in the strangulation and drug overdose deaths of three women since July. Phoenix police said he implicated himself in two others. All but one of the victims had a history of prostitution. Oklahoma detectives are trying to link Morris to four unsolved murders of prostitutes dating to 1999. “Society has an impression that your typical serial killer is Hannibal Lector,” said Steven Pitt, a forensic psychiatrist based in Scottsdale, “and the reality is nothing could be further from the truth. Serial killers come in all sizes, shapes and forms.” Motivations can range from anger to revenge to sexual gratification to power, said Pitt, who is not involved with the Morris case.