Albuquerque Police Investigate Teenager’s Death in Standoff

The police in Albuquerque said they were investigating whether their tactics during a standoff last week contributed to a house fire in which a teenager died, and called for patience from protesters who believe he was shot.

The police on Sunday identified the teenager, Brett Rosenau, 15, and said the preliminary results of an autopsy determined that the cause of death was smoke inhalation.

In a statement, the department said he “was not shot by anyone” during the standoff, in which officers arrested a man they had been seeking, Qiaunt Kelley, 27, on a warrant for a parole violation.

“I know many people in our community are hurting right now, and appreciate everyone’s patience while the incident is thoroughly investigated,” Chief Harold Medina said in the statement. “If any of our actions inadvertently contributed to his death, we will take steps to ensure this never happens again.”

The episode on Thursday renewed scrutiny of the department’s track record. That record was the subject of a 2014 agreement with the U.S. Department of Justice to introduce reforms and oversee the police’s use-of-force tactics, accountability, training and community engagement.

The agreement was reached after the Justice Department found a pattern of excessive force by the police: Twenty-three people were killed and 14 were wounded in police shootings over four years.

Under the agreement, the police are required to report to the Justice Department details of the investigation into Mr. Rosenau’s death, the police said. They will also release video footage from officers or drones that was taken during the standoff, the department said.

The release of the statement on Sunday was at least the second time in days that the chief had tried to defend his department and appeal for calm. On Thursday night, dozens of people gathered to protest the death of the teenager, who was Black, The Albuquerque Journal reported.

In a news conference on Friday, Chief Medina urged the public to wait “before a determination is made that impacts the quality of our city.”

He said that a launcher used to deploy tear gas and powder canisters into the house might have led bystanders to believe there was gunfire. “We have no indication that any shots were fired by the Albuquerque Police Department,” the chief said.

The episode unfolded late on Wednesday as detectives searched for Mr. Kelley. Mr. Kelley had violated the terms of his probation for armed carjacking and stolen vehicle charges and was also being sought in connection with a fatal shooting, a recent armed robbery and another shooting in which someone fired an automatic weapon at officers, the department said.

The police tracked him to a house in southeast Albuquerque, the most populous city in New Mexico with a population of more than half a million. They saw a gun in the car he was in and determined the motorcycle he was working on at the residence was stolen, the police statement said.

Mr. Kelley barricaded himself inside the house. Mr. Rosenau, whom the police were not seeking, followed Mr. Kelley into the house, the police said. Law enforcement officers “tried for several hours to convince them to peacefully” exit, the statement said.

Officers used a drone and robots to determine who was inside. Sgt. Michael Jones, a tactical officer, said during the news conference on Friday that officers deployed a Tri-Chamber Flameless Grenade device, commonly used in crowd control, that disperses tear gas and powder to make the environment “uncomfortable.”

The standoff ended after officers noticed smoke coming from the house, the department said. As firefighters arrived, Mr. Kelley emerged and was arrested, then was treated at a hospital for burns. Mr. Rosenau was found dead inside the house, the police said.

Albuquerque Fire Rescue is investigating the cause of the fire, which will probably take about two weeks, the police said.

Defense Technology, which makes the Tri-Chamber Flameless Grenade device, says on its website it “provides the option of delivering a pyrotechnic chemical device indoors, maximizing the chemicals’ effectiveness via heat and vaporization while minimizing or negating the chance of fire to the structure.”

The police statement said that Chief Medina acknowledged the possibility that the “devices used to introduce irritants into the home may have caused the fire.” It added that “no fires have been reported over the many years they have been used in Albuquerque.”

The American Civil Liberties Union of New Mexico said in a statement that it was asking the state’s attorney general, Hector Balderas, to investigate, saying the facts “present real questions concerning the training and experience of A.P.D.’s SWAT team and the dangers presented if tear gas canisters are used improperly.”

Barron Jones, senior policy strategist at the A.C.L.U. of New Mexico, said in the statement, “Rosenau’s loved ones deserve answers and our community must be assured that proper accountability will be applied to fatal police encounters like this one.”

The State Attorney General’s Office did not immediately respond to a request for comment.

Michael Levenson contributed reporting. Susan C. Beachy contributed research.