Homicide

Police say motive unclear after 5 members of Oklahoma family stabbed to death

This Friday, July 24, 2015 booking photo provided by the Tulsa County Sheriff's Office shows Robert Bever. A booking document filed by police in the Tulsa suburb of Broken Arrow, Okla., accuses Bever, of five counts of first-degree murder and a count of aggravated assault in the attack Wednesday night that left five family members dead. (Tulsa County Sheriff's Office via AP)

This Friday, July 24, 2015 booking photo provided by the Tulsa County Sheriff's Office shows Robert Bever. A booking document filed by police in the Tulsa suburb of Broken Arrow, Okla., accuses Bever, of five counts of first-degree murder and a count of aggravated assault in the attack Wednesday night that left five family members dead. (Tulsa County Sheriff's Office via AP)  (The Associated Press)

Police in Oklahoma say they have turned to social media posts for clues about the motive of a teenager accused in the stabbing deaths of his parents and three siblings during a late-night attack that left bodies strewn through the family's home.

A booking document filed by police in the Tulsa suburb of Broken Arrow accuses Robert Bever, 18, of five counts of first-degree murder and a count of aggravated assault in the attack Wednesday night.

Bever's 16-year-old brother also was being held. Because he is a juvenile, officers have not released his name or announced charges against him. Broken Arrow Police Cpl. Leon Calhoun said both brothers were cooperating with the investigation.