EAST LIVERPOOL, Ohio (AP) -- Investigators have determined an eastern Ohio man set a March fire that killed him and his three young sons.

Officials say 37-year-old Ulrick Estimot locked himself and his sons in their East Liverpool home before setting it on fire March 17. The arson has been ruled a murder-suicide.

The boys were ages 11, 7 and 5.

Police say Estimot poured gasoline throughout the house before igniting himself in the living room near his youngest son. The two older boys were found in an upstairs bedroom.

Police say the fire happened a day after Estimot and his girlfriend, the mother of two of his children, decided to separate.