(CNN) A high-speed getaway attempt and a reach for the waistband are said to have prompted police SWAT team members to open fire on a group of leaders of the Oregon armed occupiers.
A law enforcement official described the dramatic showdown that occurred Tuesday night on a desolate stretch of U.S. 395, some distance away from the federal wildlife refuge where the group took over federal buildings nearly a month ago.
FBI and Oregon State Police at a command center in Burns were monitoring the group when they departed the refuge to attend a town hall meeting with local residents in the town of John Day.
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For days, they watched as members of the group came and went freely from the refuge. Some went home on weekends. Ammon Bundy, the group's leader, visited family near Boise, Idaho.
"They got quite comfortable coming and going. This was a 'standoff-lite,'" said one official who was monitoring the events as they went down.
Tuesday was the first time that the combination of top leaders was all together traveling away from their base at Malheur National Wildlife Refuge, the official said.
The FBI and state police teams knew the route they were going to take. They picked a spot away from populated areas to attempt a traffic stop. One vehicle stopped on command from authorities. The second, allegedly driven by LaVoy Finicum, took off at high speed, attempting to get away.
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About a mile away, out of sight, the FBI and state police had set up a roadblock.
But Finicum, with police in hot pursuit, attempted to leave the main road and drove into a snow bank. When he emerged from the vehicle, FBI and state police ordered him to surrender. That's when, authorities say, Finicum reached down toward his waistband where he had a gun.
The SWAT team opened fire. Finicum was killed. Ryan Bundy suffered a light wound on his arm.
The shooting was captured on camera by the SWAT team. FBI and Oregon police officials are discussing possibly releasing the video, in part to counter claims by supporters that Finicum was gunned down while trying to surrender.
In all, police arrested eight people Tuesday linked to the wildlife refuge takeover: Five in the traffic stop; two others in Burns; and one in Arizona, the FBI and Oregon State Police said.
Overnight, dozens of members of the armed group left the federal refuge.
The FBI and state and federal authorities have clamped down on access roads to prevent anyone from returning.
Authorities believe perhaps 10 or fewer members of the group remain in the refuge.
On January 2, protesters took over the Malheur National Wildlife Refuge complex in eastern Oregon, in part to protest the sentencing of two ranchers and what they call government overreach when it comes to federal lands.