In April 2005, Stephen Stanko murdered his girlfriend Laura Ling, and then raped and stabbed her daughter. Shortly afterwards, he killed a friend, Henry Turner. At his trial for Laura Ling's murder, the defense called medical experts that had examined PET scans of Stanko’s brain. They revealed that he was born with a brain defect that could make him psychopathic. “48 Hours" Correspondent Troy Roberts reports. This classic "48 Hours" episode last aired on 9/1/2007. Watch all-new episodes of “48 Hours” on Saturdays, and stream on demand on Paramount+.