Seattle Seahawks star Michael Bennett on Wednesday accused the Las Vegas Police Department of assaulting him during an incident after last month’s Mayweather vs. McGregor boxing match.

The two-time Pro Bowl defensive end says he was among a group fleeing what sounded like gun shots when police officers brought him to the ground, dug a knee into his back, and threatened to “blow my fucking head off.”

Here is his account of the incident:

And here is video of the incident from TMZ:

Bennett has hired civil rights attorney John Burris and is considering filing a civil rights lawsuit. “Mr. Bennett was face down on the ground when a Las Vegas Police officer placed his gun at the back of Mr. Bennett’s head and shouted don’t move or I’ll blow your fucking head off,” Burris said in a statement. “Bennett was in total compliance and scared for his life when a second officer for no apparent reason forcefully dug his knee into Mr. Bennett’s back making it difficult for him to breathe.”

Burris continued: “Terrified and frightened, Mr. Bennett continuously asked the Officers why they were arresting him and he tried to remind them that he had rights.”

The organization Color of Change has started a petition asking Las Vegas police to release the names of the officers and any body camera footage of the incident.

Burris called the incident “exhibit A as to how every black man rich, famous or poor, unarmed and innocent can be falsely detained, arrested or even shot and killed by the police.”

As Slate’s Josh Levin noted last month, Bennett had been sitting during the national anthem at preseason games this year to continue the protest of exiled NFL quarterback Colin Kaepernick:

Bennett, who is black, decided to sit out the anthem after watching the weekend’s events in Charlottesville, explaining that “just because [Kaepernick’s] out of the league, we didn’t want to lose that message, pushing for liberty and equality for everybody. We just wanted to keep that message alive.”

In an interview with ESPN, Bennett said at the time that players were afraid to protest as Kaepernick had done because of fears about backlash from fans and the league itself. “I think a lot of players were scared of that,” he said. “Then on top of that, players feeling like he was being blackballed, people were eventually scared.”

In a profile for ESPN last year, Mina Kimes reported that Bennett was interested in politics and had been a Bernie Sanders supporter.

Philadelphia Eagles safety Malcolm Jenkins announced on Wednesday that he would be raising his fist during games “to take a stand for racial equality and the much needed reform to our criminal justice system.”

In the video, Jenkins and former wide receiver Anquan Boldin named specific practices they were protesting, including the bail system, the long-term publication of criminal records for nonviolent offenders, and lack of “police accountability.”

Kaepernick, who has yet to receive an offer to play in the NFL this year despite the fact that players with similar skill sets are almost always given roster spots and sometimes starting jobs, tweeted out Bennett’s statement.

“This violation that happened against my Brother Michael Bennett is disgusting and unjust. I stand with Michael and I stand with the people,” he said.

The NFL season starts on Thursday. Bennett’s Seahawks are scheduled to play the Green Bay Packers on Sunday.