UNIVERSITY PLACE, Wash. -- An investigation into a fire that killed two people in University Place Thursday is continuing, and a man police said was a person of interest was released.

The fire erupted early Thursday, killing 61-year-old Rachel Kalebu and a man believed to be 57-year-old John "J.J." Jones, a former NFL quarterback.

The two lived together and were longtime friends.

Following the fire, investigators first found Kalebu's body in the home's kitchen. Later in the day, the body of a man was found in the basement.

Kalebu's 23-year-old nephew, who also lived in the home, was detained by police for hours Thursday, under suspicion because his aunt filed a restraining order against him the day before the fire, police said.

Kalebu claimed her nephew was constantly threatening to harm her and she wanted him out of her house.

When Kalebu's nephew returned to the neighborhood Thursday morning, he told police he'd been sleeping in the woods nearby after getting into a fight.

Following questioning, the man was released Thursday. Pierce County authorities said the man is "still under the umbrella of suspicion."

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The Pierce County Medical Examiner has not released the cause of death of the two victims. It is not known if the victims' death was related to the fire or if there was violence in the home before the fire erupted.

A neighbor told KIRO she heard people shouting and running through the yard before the fire started.

"About 1:30 in the morning, I heard several loud bang-popping noises. At first I thought they were fireworks, but since I'm familiar with firearms, it sounded like maybe muffled gunshots," said neighbor Liz Erb.

A police officer guarded the home overnight. Investigators will continue searching for clues to determine whether or not the fire was deliberately set.