BROKEN ARROW, Oklahoma (NEWSCHANNEL 3) - We're learning more information about a mass murder in Broken Arrow, Oklahoma.
Documents say one of the brothers charged in the stabbing deaths of his parents and three siblings told police that plans for the killing were on a thumb drive inside the family's home.
One of the brothers "spontaneously uttered" that the plans were on the drive in a bedroom.
18-year-old Robert Bever and his 16-year-old brother, Michael, are charged with first-degree murder in the July 22nd attack.
A 2-year-old sister wasn't harmed in the attack, and a 13-year-old sister survived.