One called it murder. Some need more information. How policing experts see the Pretti shooting.

In Alex Pretti’s final moments, he was down on all fours on a frigid Minneapolis street, with multiple federal agents on top of him.

One agent emerged from the scrum with a gun taken from Pretti’s holster, a bystander’s video shows. An instant later, another agent opened fire at point-blank range. Then more shots were fired, leaving Pretti motionless on the sidewalk. Pretti, a 37-year-old intensive care nurse, was soon pronounced dead.

Some policing experts said the shooting appeared unjustified and one said it amounted to murder. Others said they could not form a judgment until they knew more, particularly what threat the agent who fired thought he faced at that moment. The killing of Pretti, the second fatal shooting by a federal officer in Minneapolis this month, has also revived concerns about whether immigration enforcement officers are properly trained to deal with protesters.

“This video raises a lot of questions,” said Chuck Wexler, executive director of the Police Executive Research Forum, a Washington, D.C.-based organization of current and former law enforcement officials focused on improving policing.

“What happened that made these agents feel threatened? That should be the question that everyone is trying to get to the bottom of.”

Whether the killing will be the subject of a thorough investigation remains an open question. Multiple Trump administration officials have already defended the actions of the Border Patrol agent who opened fire, in some cases making claims that run counter to videos of the confrontation.

Homeland Security Secretary Kristi Noem said her agency will lead the investigation, which is unusual; based on previous practice, the FBI would take the lead in a shooting involving a Department of Homeland Security officer. Minnesota state investigators said they were blocked from accessing the shooting scene despite having a warrant, and they asked a judge to stop federal authorities from destroying or altering evidence.

Tom Nolan, a former Boston police commander and criminology professor who once advised DHS on civil rights issues, said Saturday’s shooting was part of a larger pattern in which Immigration and Customs Enforcement and Customs and Border Protection officers, who historically have focused on targeted enforcement of immigration violations, appear to be ill-equipped to properly handle demonstrators. The failing is evident, he said, in officers’ smashing car windows, shoving people to the ground and deploying chemical sprays in people’s faces.

“It’s clear that these people who we’re seeing, these federal government officers in Minneapolis, are obviously overwhelmed and poorly trained and inexperienced,” Nolan said.

“So when you see them on the street engaging with people, that’s a security concern right there, because they don’t know what they’re doing,” he said.

Jason Houser, a former DHS counterterrorism official and ICE chief of staff under President Joe Biden, said Saturday’s shooting was the latest example of federal immigration agents who are thrust into encounters with protesters handling them in ways that reveal a lack of centralized command, coordination with local law enforcement and preparation for such situations.

“What I clearly see is Border Patrol agents put in harm’s way when they have minimal training to the circumstances they’re being pushed into,” Houser said.

DHS did not immediately respond to a request for comment. Agency officials have previously defended officers’ work and said they seek to de-escalate encounters with protesters as they face unprecedented threats while they carry out President Donald Trump’s far-reaching crackdown on immigrants without legal status.

Border Patrol commander Gregory Bovino said Sunday that the agents involved in the shooting had been pursuing an Ecuadorian national wanted on allegations of domestic assault, intentional implication of bodily harm and disorderly conduct. An agent who fired the shots had been serving with the Border Patrol for eight years, with “extensive training as a range safety officer and less lethal officer,” Bovino said.

At a news conference, Bovino was asked why it was necessary to fire so many times at a man who appeared to be unarmed.

“The investigation is going to uncover all those facts, things like how many shots were fired, where were the weapons,” he said. “Those are the facts that will come out of the investigation.”

The deadly confrontation began after Pretti, who had been recording officers in the street, stepped in between one of them and a person who had been pushed to the ground.

Tod Burke, a criminologist and former police officer, said that despite all the video, there is still a lot that remains unknown, including what the officers and Pretti said — and what the officers knew before the shots started.

“Once that one gun was removed, I can’t understand what any other threat was, but I don’t know what was going on in that scrum for them to feel that shooting was the way to resolve the situation,” Burke said.

Mickie McComb, a former New Jersey state trooper who now works as an expert witness on use-of-force cases, said he believed the videos show that the officers had no reason to open fire.

“If you disarm him and he’s not reaching for a weapon, you can’t use deadly force,” McComb said.

Nolan, the former Boston police commander, put it even more bluntly.

“Under no circumstances was this a justified shooting,” he said. “It was a stone-cold murder. It’s a bad shoot.”

Pretti, who worked in the intensive care unit at the Veterans Affairs hospital in Minneapolis, had a permit to carry a gun, local officials said. Policing experts said that when officers are trying to arrest people found to have firearms, they are taught to alert their fellow officers and then draw their own guns and order the people to drop theirs or to try to disarm them.

“You cannot assume that, because an officer has ‘gun one,’ the individual is now unarmed,” said David Klinger, a retired police officer-turned-criminology professor at the University of Missouri-St. Louis.

“This was tense, this was uncertain, this was rapidly evolving,” Klinger said. “We know this ended with a use of deadly force. I want to understand the decisions people made and how things went downstream from those decisions.”