W. Joseph Astarita, 41, displayed a slight smile when the jury returned its verdict after less than a day of deliberations. He left the courthouse without comment.
Astarita was charged with making false statements and obstruction of justice after telling investigators he did not fire the shots that missed Robert "LaVoy" Finicum.
His attorneys, Robert Cary and David Angeli, stressed to jurors that no eyewitnesses saw Astarita fire his weapon, and there was no ballistic evidence linking a bullet to his rifle.
"We are grateful to the men and women of the jury who saw through a case that should have never been brought," the lawyers said in a joint statement. "Joe Astarita is innocent and it was our privilege and honor to represent him."
Assistant U.S. Attorney Gary Sussman declined comment after the verdict.
The verdict marked another high-profile loss for prosecutors in cases related to the Bundy family, which opposes federal control of public lands.
Ammon and Ryan Bundy plus five other occupiers were found not guilty of conspiracy and gun charges in a trial that ended two years ago.
Earlier this year, charges stemming the Bundys' armed standoff with government agents in Nevada were dropped.
U.S. Attorney for Oregon Billy Williams said he strongly believed the Astarita case needed to be tried.
"Our system of justice relies on the absolute integrity of law enforcement officials at all levels of government," he said.
The errant shots came as Finicum left his pickup while authorities tried to arrest him at a roadblock on Jan. 26, 2016. Oregon State Police fatally shot Finicum seconds later - a killing that was deemed legally justified.
Investigators looking into the shooting were able to identify those responsible for six of the eight rounds fired that day. No one owned up to the other two. After an investigation, Astarita was indicted in June 2017.
Prosecutors said he was the only one who could have fired the shots. Their assertion was based on FBI aerial surveillance videos and forensic analysis tracing a bullet back to his position.
Finicum and other occupiers led by Ammon Bundy seized the refuge on Jan. 2, 2016, to protest the imprisonment of two Oregon ranchers who had set fires. President Donald Trump recently pardoned those men, Dwight and Steven Hammond.
On Jan. 26, the FBI learned that Finicum, Bundy and other key figures were leaving the refuge in two vehicles to meet with a sheriff sympathetic to their cause.
Police stopped the vehicles, and several people surrendered, including Ammon Bundy. But Finicum fled at more than 70 mph with Bundy's brother Ryan and several others, authorities say.
Roughly a mile down the road, Finicum swerved to avoid a roadblock, nearly hit an FBI agent and careened into a snowbank. Three shots, none fired by Astarita, hit the pickup during the chaos.
The two disputed gunshots rang out as Finicum emerged from his pickup and yelled, "Go ahead and shoot me!"
One bullet missed everything and was never recovered. The other struck the pickup and shattered a window.
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