An American man was killed when a Mexican police officer opened fire on the car he was driving in Ciudad Juárez, across the border from El Paso, Texas, Mexican authorities said Monday.

The regional prosecutor in Chihuahua state, Carlos Manuel Salas, said the shooting happened Sunday while the police officer was accompanying a staff member from the prosecutor’s office who was serving a warrant. The two were on foot when a Mustang with New Mexico license plates suddenly accelerated in their direction, according to Mr. Salas. He said the officer opened fire as the driver tried to flee.

Mr. Salas said the officer was in custody and that the shooting, which was captured on video by a passenger in the car, would be investigated by the state attorney general’s internal affairs division. At the press conference Mr. Salas described the incident as “deplorable” and urged the public to refrain from drawing conclusions until the investigation is complete.

But he appears to have offered to defend the officer, whose name has not been released. According to Mr. Salas, the vehicle was traveling at high speed and skidded as it approached the officer, almost hitting him. The driver was wearing a hood, he said.

“Why would you speed up?” he asked. “Why would you drive at that speed?”

Mr. Salas argued that police would also likely respond with force if something similar happened in another country, including the United States.

Authorities have not identified the man who was killed, describing him only as a nurse’s aide from El Paso. But Mexican news outlets reported that his name is Julián Alfredo Rodríguez Medina. News reports say the man and at least one of the two passengers in the car had family members who lived nearby.

In an interview for a newspaper Diarya man who identified himself as the driver’s brother and who said he was in the car asked state officials to press charges against the officer.

The man, who identified himself only as Jorge AR, said he and the other people in the car had gone out to eat when they were shot at. He said they posed no threat and were a considerable distance from the officer when he opened fire.

“At no point did we threaten him, nor did we shout at him, nor did we slide the car,” El Diario quoted the man as saying.

Mr. Salas, the prosecutor, said American officials had been notified of the shooting in accordance with protocol. A spokesman for the United States Embassy said in a statement that officials are “closely following the local authorities’ investigation into the reported homicide.”

The incident is the latest in a series of violent deaths of Americans in Mexico.

Last week, a 62-year-old man from Rockford, Ill., was shot at a highway checkpoint in the state of Zacatecas that his family said was run by a criminal organization. A few days earlier, two American citizens and a Mexican citizen were killed in the state of Durango in an ambush that also left American teenager seriously injured.

Mexico’s president, Claudia Sheinbaum, has vowed to curb the violence that has gripped much of the country. While officials often cite drug-trafficking cartels as the cause of the bloodshed, experts say police-involved violence is also not uncommon.

Sunday’s shooting of an American sparked a heated debate after a video taken by a passenger was posted on social media. Many called for harsh consequences for the detained police officer, and some commentators threatened death.

Authorities on Monday announced an arrest in the Dec. 27 shooting in Durango. They identified the suspect as Iram Uranga Armendáriz, and said the shooting stemmed from a dispute over a debt related to a land deal.

Mr Uranga is accused of shooting two men in the head, then two others – including a teenager – from behind as they tried to flee on foot. The teenager, Jason Peña, 14, of Chicago, was said to be in critical condition at a Houston hospital on Monday.

Emiliano Rodríguez Mega contributed reporting.