TULSA, Oklahoma - News On 6 has obtained more documents in the case against the Bever brothers accused of killing five members of their family.

In search warrants filed Thursday, Broken Arrow police say they recovered six computers, a partially dismantled laptop, an external drive and a thumb drive from the family's home.

Police say the home had video surveillance cameras near where three of the victims died. The documents say it appears the cameras were connected to one or more of the computers.

Police say they are looking to see if there are any video or audio recordings from that night or evidence the attack was planned.

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.

Detectives 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. 

Public defenders entered not-guilty pleas on behalf of Robert and Michael Bever.