DALLAS (AP) - Police say they believe a man who killed six family members in a Christmas Day shooting at a Texas apartment attempted to stage the scene by placing one of the guns used in the hand of his deceased brother-in-law before killing himself.

Grapevine police Sgt. Robert Eberling says evidence shows 56-year-old Aziz Yazdanpanah was the only one to fire the two weapons found at the scene. A gun was also found in his hand.

Eberling says he thinks Yazdanpanah "was probably overwhelmed when it was all said and done and decided to take his life instead."

Yazdanpanah's brother-in-law was shot multiple times in the head, chest and stomach. Authorities say Yazdanpanah also killed his estranged wife, their two teenage children, his wife's sister and his niece.