b'Teen Matthew Bernard kills his mother, sister, nephew, and the family dog. The question remains as to why. Police are looking to data from a recovered cell phone for an explanation. Joining Nancy Grace today: Ken Belkin, NY criminal defense attorney; John Cardillo, Former NYPD; Dr. Caryn Stark,\\xa0Psychologist; Dr.\\xa0Michelle Dupree, Medical Examiner; reporter Levi Page Investigative Reporter Crime Online.com.'