A body was found inside the burned-out cabin Tuesday night where Christopher Jordan Dorner was believed to have kept law enforcement authorities at bay before officers fired tear gas into the structure, a source told The Times.

The body, which was found in the charred rubble of the mountainside cabin, was not positively identified, the source said. The process of determining whether the body is that of the former Los Angeles Police Department officer could take hours or even days, the source said.

As authorities moved into the cabin earlier Tuesday, they heard a single gunshot.

UPDATE: Confusion over whether body was found

According to a law enforcement source, police had broken down windows, fired tear gas into the cabin and blasted over a loud speaker, urging Dorner to surrender. When they got no response, police deployed a vehicle to rip down the walls of the cabin "one by one, like peeling an onion," a law enforcement official said.

By the time they got to the last wall, authorities heard a single gunshot, the source said. Then flames began to spread through the structure, and gunshots, probably set off by the fire, were heard.

As darkness descended on the mountainside, Dorner's body had not been found, authorities said. Police were planning to focus their search in the basement area, the source said.

PHOTOS: Manhunt for ex-LAPD officer

Earlier Tuesday, a tall plume of smoke was rising as flames consumed the wood-paneled cabin. Hundreds of law enforcement personnel had swooped down on the site near Big Bear after the gun battles between Dorner and officers that broke out in the snow-covered mountains where the fugitive had been eluding a massive manhunt since his truck was found burning in the area late last week.