In a video shared on social media early Tuesday, a Minneapolis police officer pins his knee against the neck of a black man who appears to be struggling to breathe on the ground.

“Being black in America should not be a death sentence,” Minneapolis Mayor Jacob Frey (D) said during a news conference Tuesday.

The incident began when two officers arrived at the 3700 block of Chicago Avenue South around 8 p.m.

“Officers were able to get the suspect into handcuffs and realized that the suspect was suffering a medical distress,” a Minneapolis police spokesman said in a news briefing early Tuesday.

Darnella Frazier was on her way to see friends when she saw the incident unfolding outside of a Cup Foods grocery store on the south side of Minneapolis.

“When I walked up, he was already on the ground,” Frazier said in a Facebook video.

Bystanders who remained in front of Cup Foods pointed at the two officers and said the incident would haunt them “for the rest of your life.”.

“The police killed him, bro, right in front of everybody,” Frazier said on Facebook.

During Tuesday’s news conference with the mayor, Minneapolis Police Chief Medaria Arradondo said he had decided to ask the FBI to investigate after receiving “additional information” on the incident from a community source that “just provided more context than the information I had preliminary.” He declined to elaborate further.

The officers involved, who have not been publicly identified, were placed on paid administrative leave, the police chief said.

“If you’re sad, I get it,” Frey said