The state police SWAT officer who investigators say fired five times at refuge occupation spokesman Robert "LaVoy" Finicum said Monday he second-guessed himself when he learned of an unaccounted-for bullet hole in the roof of Finicum's truck.

In the days after the Jan. 26, 2016, shooting in Harney County, the officer wracked his brain trying to figure out how it could have occurred, considering that none of the FBI's Hostage Rescue Team agents at the scene said they had fired any shots.

"I never thought I did it, but there were times I was thinking, 'I don't know. This doesn't make any sense,''' he said. "If that was going to be attributed to me and I had no recollection of it ... could I continue in this profession?''

When he learned investigators had tracked all his shots and the magazine of his AR-15 rifle was missing five bullets, he said he told them: "The FBI has a big effing problem, and this is serious.''

The testimony from "Officer 1" - the only identification of the SWAT officer used in court because of government concerns over militia threats - is crucial to the prosecution's case in the trial of an FBI agent at the scene that day.

Agent W. Joseph Astarita is accused of lying about having fired two disputed shots at Finicum's truck as state police and the FBI moved to arrest leaders of armed occupation of the Malheur National Wildlife Refuge. One struck the roof and one missed entirely.

Astarita's lawyers have argued that other people at the scene, and most likely Officer 1, could have fired the shots.

Officer 1 said he knew he hadn't fired the shots in question because investigators found only 24 rounds remaining in the magazine of his AR-15 rifle, which he said he loaded with 29 rounds....