Brother says plans for killings were on thumb drive

BROKEN ARROW, Okla. (AP) – Documents say one of the brothers charged in the stabbing deaths of his parents and three siblings in Broken Arrow told police that plans for the killing were on a thumb drive inside the family’s home.

An affidavit for a search warrant filed Thursday in the July 22 attack in Broken Arrow says one of the brothers "spontaneously uttered" that the plans were on the drive in a bedroom. A police investigator wrote that authorities would likely find evidence related to the planning of a "mass homicide" at the home.

Eighteen-year-old Robert Bever and his 16-year-old brother, Michael Bever, are charged with first-degree murder in the deaths. Their defense attorneys couldn’t immediately be reached late Thursday.

A 2-year-old sister wasn’t harmed in the attack, and a 13-year-old sister survived.