(CNN) -- Authorities in Washington state found a body inside a fortified bunker where a man suspected of killing his wife and daughter was believed to be hiding, King County Sheriff's Office Sgt. Katie Larson said.
Deputies had been waiting out Peter Keller, who was believed to have been holed up inside the bunker near Seattle.
The body deputies found appeared to have suffered a self-inflicted gunshot wound, Larson said, but it was not immediately confirmed if it was Keller.
Deputies earlier said they had Keller, 41, contained inside the bunker.
Authorities fired tear gas late Friday into the bunker, set into the Cascade foothills about 25 miles east of Seattle. It was unclear whether the gas went deep enough to have any effect.
Keller has not been seen since Sunday following a fire at his home, where the bodies of his wife and teenage daughter were discovered.
His standoff with authorities began Friday after investigators found evidence that led them to the bunker near Rattlesnake Ridge Trail, according to the King County Sheriff's Office.
Authorities didn't immediately send deputies in because of safety concerns.
Investigators do not have a clear motive for the slayings, according to Sgt. Cindi West of the King County Sheriff's Office
Keller, who does not have a criminal record, has been described as a survivalist by some relatives, West said.
"We gathered he had a doomsday attitude ... family and friends have indicated he thought the world was going to end at some point," West said.
Keller likely had plenty of arms and supplies in the bunker, officials said.
"We know he in the past has had a number of rifles, scopes and handguns. He purchased some kind of bulletproof vest," West said.
Clues to Keller's whereabouts came while investigators were processing evidence at his house, authorities said. People in the area also reported seeing Keller's pickup truck near the trailhead.
"This isn't a hole in the ground. This is a large built-up structure," Sheriff Steven D. Strachan said of the bunker. "But hidden. It took some time to find it. In fact our tactical team smelled the wood smoke coming before they actually saw it."
Strachan said Keller's house nearby was set afire Sunday after the slayings, but it failed to spread beyond the kitchen. Authorities found a hard drive with photos, he told CNN Seattle affiliate KING.
One photo was enhanced and it aided in the search for Keller, who authorities said had been building the bunker for at least eight years.
"We believe he has taken pictures from 2004 to the present day," West. said
She said she did not know the precise size of the bunker, made partially of earth and logs.
"We believe it is very large," the spokeswoman said. "He has had plenty of time to work on it."
The sheriff's office this week obtained an arrest warrant for Keller stipulating two counts of first-degree murder and first-degree arson.