Federal agents shot and killed a 37-year-old Minneapolis resident, Alex Jeffrey Pretti, at about 9 a.m. Central time on Saturday morning. A video shared with The New York Times by a witness and her lawyer, as well as other video footage posted on social media, documents the violent scene, where agents appear to fire at least 10 shots in a span of five seconds.

The footage seems to contradict the Department of Homeland Security’s account of the encounter, which the agency said began after an individual armed with a handgun approached the federal agents with the intent to “massacre” them.

48 seconds before shooting

Still from video shared with The Times. The New York Times

Videos show a small group of civilians standing in the middle of a street where a person was detained on the ground; the civilians are speaking to federal agents. Mr. Pretti appears to be filming the scene, and he walks closer to the federal agents while holding his phone.

Then an agent shoves two civilians from one side of the street to the other, pushing them toward a white S.U.V.

28 seconds before

Still from video shared with The Times. The New York Times

For a second time, the agent pushes the civilian with the orange backpack. The civilian falls to the ground near the white S.U.V.

25 seconds before

Still from video by Philophon via Reddit. The New York Times

Mr. Pretti tries to put himself between the D.H.S. agent and the two civilians. Footage shows the same agent squirting pepper spray in the direction of Mr. Pretti’s face. (This agent will later fire shots at Mr. Pretti.)

Mr. Pretti is holding his phone in one hand, and he holds his other hand up to shield himself from the spray.

23 seconds before

Still from video shared with The Times. The New York Times

Mr. Pretti appears to be trying to help the civilian with the orange backpack stand back up as the agent continues to pepper-spray the group.

17 seconds before

Still from video by witness shared with The Times. The New York Times

Several agents grab Mr. Pretti, who is still holding his phone. Additional agents approach and try to pin Mr. Pretti to the ground.

11 seconds before

Still from video by Philophon via Reddit. The New York Times

Mr. Pretti is surrounded by a group of seven agents, some of whom have wrestled him to the ground. One of the agents, who wears a gray coat, gets closer to Mr. Pretti. The agent’s hands are empty as he reaches for Mr. Pretti, while the other agents hold Mr. Pretti down on his knees. At the same time, another agent strikes Mr. Pretti repeatedly with a pepper spray canister.

1 second before

Still from video shared with The Times. The New York Times

An eighth agent joins the group. The agent in the gray coat appears to pull a gun from near Mr. Pretti’s right hip. The agent then begins to move away from the skirmish with the weapon.

At the same time, another agent unholsters his firearm and points it at Mr. Pretti’s back.

First shot fired

Still from witness video via Associated Press. The New York Times

The agent in the gray coat removes the weapon from the scene. It matches the profile of a gun that D.H.S. says belonged to Mr. Pretti. Then, while Mr. Pretti is on his knees and restrained, the agent standing directly above him appears to fire one shot at Mr. Pretti at close range. He immediately fires three additional shots.

The diagram below shows the position of the agents, Mr. Pretti and other civilians at this moment.

The New York Times

Additional shots fired

Still from video shared with The Times. The New York Times

Several agents have moved away from Mr. Pretti, who has collapsed. Another agent — the same one who shoved the civilians into the street and pepper-sprayed Mr. Pretti — unholsters his gun and fires at Mr. Pretti. The first agent also fires additional shots. Together, they fire six more shots at Mr. Pretti while he lies motionless on the ground.

At least 10 shots appear to have been fired within five seconds. By the moment of the 10th shot, the agent who moved away with the weapon has crossed the street.

Mr. Pretti is the second person to be shot and killed by a federal agent in Minnesota in recent weeks. Footage of Mr. Pretti’s death in Minneapolis was posted on social media almost immediately after the shooting.

The Homeland Security Department said that the episode began after a man approached Border Patrol agents with a handgun, and that an agent fired “defensive shots.” Another encounter in Minneapolis this month, in which a Venezuelan man was shot in the leg by a federal agent, was also characterized as “defensive” by the department.

Gov. Tim Walz, Democrat of Minnesota, disputed the claims by federal officials that Mr. Pretti had posed a threat. He accused “the most powerful people in the federal government” of “spinning stories and putting up pictures.”

Chief Brian O’Hara of the Minneapolis Police Department said that Mr. Pretti was an American citizen with no criminal record and that he had a valid firearms permit. Under Minnesota law, citizens can legally carry a handgun in public, without concealment, if they have a permit.

As with the fatal shooting of Renee Good, local and state authorities in Minnesota say that they have been impeded by D.H.S. from investigating the killing of Mr. Pretti, and that they have been cut off from access to crucial evidence and facts.

Large crowds of protesters gathered throughout Saturday at the site of Mr. Pretti’s shooting. On Sunday afternoon, around 1,000 people packed Government Plaza in downtown Minneapolis to protest the presence of federal agents in the city and to call for justice for Ms. Good and Mr. Pretti.