(CNN) The investigation into the death of LaVoy Finicum, killed during the occupation of Malheur National Wildlife Refuge in January, shows that the three fatal shots fired by Oregon State Police were justified "and, in fact, necessary," Malheur County District Attorney Dan Norris said Tuesday.
But the inspector general of the U.S. Justice Department is investigating how FBI agents also fired two shots, but neither struck Finicum, local authorities said.
"The question of who fired these shots has not been resolved," Greg Bretzing, the FBI's special agent in charge in Oregon, said Tuesday. "I can assure that the FBI is cooperating fully with the office of inspector general."
In total, eight shots were fired, though flash-bang grenades and gas projectiles were also deployed to ensure three remaining occupants in Finicum's truck surrendered peacefully, the investigation showed.
Authorities dismissed accounts that law officers fired more than 100 rounds of bullets, suggesting that the flash-bang grenades and projectiles may have been mistaken for gunfire.
The police provided reporters with video of Finicum's truck barreling at an estimated 70 mph toward a roadblock of two trucks forming a V in the middle of the road. A third vehicle was parked behind those trucks.
The video reveals a fast exchange of words between Finicum behind the wheel and a female passenger inside the truck.
"Hang on!" Finicum tells the occupants inside the truck as a shot is fired, apparently by authorities. He is driving the truck.
"OK, they're shooting," the woman says.
Finicum was driving one of two vehicles authorities tracked leaving the Malheur refuge January 26. One -- carrying Ammon Bundy, the protest leader whose father, Cliven, was at the center of a similar armed standoff in 2014 -- pulled over to a stop, and the people inside came out peacefully.
The officers believed Finicum "planned to crash through or otherwise evade the roadblock" and could injure or kill law enforcement officers at the scene, Norris said. They fired at the truck three times but hit no one inside the truck.
Just before Finicum arrived at the roadblock, he veered left into a snowbank at an estimated 50 mph, narrowly missing a federal agent who was trying to get out of the way, the video showed.
As Finicum exited his vehicle with a loaded Ruger 9 mm handgun in the left-hand interior pocket of his jacket, he was instructed to get on the ground three times, Deschutes County Sheriff L. Shane Nelson said.
The video also shows Finicum exiting the truck.
"Stay down," the woman tells the two other people inside the truck.
Then gunfire is heard.
"Are they shooting him?" the woman asks.
A transcript provided Tuesday shows the exchange between Finicum and officers after he exits his truck.
"Go ahead and shoot me," Finicum tells the officers on at least four occasions.
"Get on the ground," officers tell Finicum on at least two occasions, according to the transcript.
"You're gonna have to shoot me," Finicum tells the officers at least twice.
Despite Finicum defying those orders and reaching toward the pocket containing the gun, two nearby state police officers did not immediately open fire, and a third officer attempted to move in with a Taser, Nelson said. Finicum was out of range of the Taser, he said.
When Finicum reached for his pocket a third time, two troopers opened fire, hitting him three times in the back -- in the left shoulder, below the neck and on the right side of his lower back.
FBI agents fired the other two shots before Finicum exited the vehicle, Nelson said. One missed the truck, while the other hit the truck's roof, the sheriff said.
Authorities from both the Deschutes County Sheriff's Office and the Inspector General of the U.S. Department of Justice are looking into what the FBI agents failed to disclose in their ongoing investigations, according to Nelson.
The agents, interviewed at least three separate times by the major incident team in the days after the shooting, never disclosed that they fired shots, Nelson said.
"A particular concern to all of us is that the FBI [Hostage Rescue Team] operators did not disclose their shots to our investigators, nor did they disclose specific actions that they took after the shooting," Nelson said.
The names of the law enforcement officers involved are not being released out of concern for "their safety and the safety of their families," Norris said, adding that there have been threats against the officers, including rewards offered by extremist groups.
Finicum was the lone armed occupier of the Malheur National Wildlife Refuge to die at law enforcement's hands in the 41-day standoff.
The occupation of part of the federal wildlife refuge ended peacefully February 11 when the last four occupiers surrendered to authorities. They had been among a larger group who took over the refuge's headquarters in a defiant protest of federal land policies. They decried the arson convictions of father-and-son ranchers Dwight and Steven Hammond (though the Hammonds insisted they didn't want help from the occupiers, led by Ammon Bundy.)
For weeks, authorities positioned themselves outside a Malheur National Wildlife Refuge building near Burns -- not charging in to get the occupiers but not giving them a free pass to stay or easily leave either.
Some of the occupiers insisted they planned to stay as long as it took and that they were prepared to die.
Finicum was the only one who did.
The Arizona rancher and published author left behind 11 children, some of whom were adopted. And this family -- "like the Brady Bunch on steroids," Finicum told CNN in December -- was growing, with two grandchildren on the way.
"So I've got a lot to live for," he said.
Finicum remained defiant, at times sitting outside the occupiers' Malheur refuge compound in a rocking chair, a rifle in his hands.
"I'm here to make it easy for the FBI to find me," he said, adding that he wouldn't use the rifle "unless someone points a weapon at me."
While Finicum stated he felt the ordeal could "be peacefully resolved," there was one outcome he couldn't envision: time behind bars.
"I'm just not going to prison," Finicum said. "Look at the stars. There's no way I'm going to sit in a concrete cell where I can't see the stars and roll out my bedroll on the ground. That's just not going to happen.
"I want to be able to get up in the morning and throw my saddle on my horse and go check on my cows. It's OK. I've lived a good life. God's been gracious to me."