NORTHFIELD CENTER, Ohio -- The house explosion that led to the discovery of the bodies of two young girls and their parents is being investigated as a murder-suicide, according to Summit County Medical Examiner records.

Records also show that Jeff Mather, 43, had recent struggles with mental illness and threatened to kill himself before being admitted to a mental health facility.

Investigators found him dead on the first floor of the home with a charred gas can next to his body, the records say. Northfield Center Fire Chief Frank Risko said the fire started on the first floor.

Mather's wife, Cynthia, 43, and two children, Alyson, 12, and Ruthie, 8, died in the fire. Investigators believe they were on the second floor when the fire started and their bodies fell to the first floor after the second floor collapsed, according to the records.

The Ohio Fire Marshal ruled Wednesday that the fire was arson. The medical examiner has not made an official ruling on the deaths.

Jeff Mather attempted suicide in December after his role changed at the Swagelok in Solon where he worked, the records say. He told authorities he had been depressed for a few months.

Prior to that, Jeff Mather had no history of mental illness, marital or financial problems, according to the records. Cynthia and Jeff were married for about 20 years.

Swagelok released a statement about Jeff Mather's death on Thursday.

"This is a tragic situation and we extend our deepest sympathies to the friends and family. We are deeply saddened by this event," Swagelok spokeswoman Theresa Polacheck said in an emailed statement. "Our focus is to support our associates through this difficult time."

Mather, a deacon for 13 years at The Rock Community Church in Garfield Heights, went to the Cleveland Metroparks Rocky River Reservation in early December with a rifle, according to the medical examiner. He ended up at the Lagoon Picnic Area in Brook Park, according to a Metroparks Ranger report.

He told investigators at the time that "dark voices" that told him to shoot himself, medical examiner records say.

Another person at the park saw Mather with the shotgun and asked if he needed help. The man eventually called park rangers for help so he didn't hurt himself. The rangers took his rifle, and Mather spent three days at Windsor Laurelwood Center for Behavioral Medicine in Willoughby.

Mather returned to work on Jan. 4.

Cynthia Mather's sister texted her Jan. 9 to see how things were going. Cynthia Mather replied that things were going poorly with her husband, the records say.

The sister said she tried to call Cynthia Mather three times on Monday and never got through. The family's home at 7486 Skyhaven Road exploded that day.