An eastern Ohio man recently separated from his longtime girlfriend set himself and his house on fire two months ago, killing him and his three young sons, investigators have concluded.

The March 17 arson was ruled a murder-suicide this week after investigators determined that 37-year-old Ulrick Estimot locked the house's front and back doors, poured gasoline throughout the home and set himself on fire, East Liverpool Police Chief John Lane said.

The Columbiana County Coroner said Estimot and the boys — 11-year-old Trey, 7-year-old Terrell and 5-year-old Trenton — died of smoke inhalation.

Lane said the fire happened a day after Estimot and the girlfriend, the mother of the two younger boys, ended their relationship. Estimot gave no indication to others about his plans, but he expressed concern to his girlfriend, Angela Latshaw, about being able to raise the boys, Lane said.

"He was afraid of being alone without her," Lane said.

Police said the fire began in the living room, where the bodies of Estimot and his youngest son were found. The two older boys' bodies were found in an upstairs bedroom.

A melted plastic gas can was found near the top of the stairs. Gasoline was found on Estimot's pants and shoes, and a lighter and cellphone were underneath his body. Gasoline also had been poured on the front of bedroom doors, authorities said.

Latshaw told police she arrived at the locked house and heard the two older boys screaming. A bystander kicked in the door as Latshaw "attempted to go into the fire to die with her children," Lane said.

The bystander held her back as police and firefighters attempted to enter the house. Officials said they were held back by intense heat and flames.