An Oklahoma couple considered "primary suspects" in last week's killings of their six children faced growing financial pressures and the husband experienced recurring pain from a workplace head injury, according to family members.

Eight people were found dead Thursday in a burning home in a Tulsa-area suburb in what authorities are investigating as a murder-suicide. The Broken Arrow Police Department on Sunday identified the two adults as Brian and Brittney Nelson but provided no new information on whether both adults were involved in the killings of the children, who ranged in age from 1 to 13.

Brian Nelson's parents, Danny and Marilyn Nelson, told the Tulsa World that their son had asked if they could babysit their grandchildren at 5 p.m. Thursday, the day of the fire.

"Five came and went. Then it was 6. I texted them — no responses," Danny Nelson said. "I turned on the 6 o’clock news, and they said there had been a fire near Hickory and Galveston in Broken Arrow. That’s where my son lives."

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Police have not released the names of the children who died but the Nelsons identified them as grandson Brian II, age 13; granddaughter Brantley, 9; grandsons Vegeta, 7, Ragnar, 5, and Kurgan, 2; and granddaughter Britannica, 1.

All six children were found dead in a burning back bedroom and the two adults were found in the front of the home. Authorities said causes of death were still pending but they don't believe anyone died from the fire.

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Brian and Brittney Nelson had filed for bankruptcy in 2020, listing $8,803 in assets versus nearly $138,000 in liabilities, most of which was unpaid student loans, the newspaper reported. Both indicated they were unemployed at the time, the filing said.

The bankruptcy filing also listed nine guns as assets.

Years ago, Brian Nelson had suffered a concussion while stocking dairy refrigerators at a large retail chain and had been plagued by severe headaches ever since, his parents said.

"I want people to know that at one time he had all his brain together," Marilyn Nelson said. "I just don’t understand why they did what they did. I just don’t understand why he ended up in that situation. I talk to God all the time — and I just don’t understand."