What Motivated Son Of Sam To Kill?

What motivated serial killer David Berkowitz to kill? While in custody, Berkowitz claimed that his neighbor, Sam Carr, owned a black Labrador Retriever that Berkowitz believed was talking to him and instructing him to kill. “Then he came up with this Son of Sam thing. I still can’t make heads or tails out of it,” NYPD Bronx Homicide Detective Richard Paul told “Mark of a Killer.”