TULSA, Oklahoma - Tulsa County prosecutors filed five first-degree murder charges against two Broken Arrow brothers in the deaths of their parents and three siblings.

Robert Davis Bever, 18, and Michael John Bever, 16, each face five counts in the stabbing deaths of their parents and three siblings at their Broken Arrow home on July 22, 2015.

Prosecutors also charged Robert and Michael Bever with Assault and Battery With Intent to Kill for multiple stabbings of their 13-year-old sister. She survived.

Detective say the brothers acted together when they killed their parents, David and April Bever, and their siblings Daniel, Christopher and Victoria. They are also charged in concert in the attack on the surviving sister. 

Under Oklahoma law, a 16-year-old is charged with first-degree murder as an adult, according to a news release from prosecutors.