The New York City Police Department announced Wednesday that it has launched an internal investigation into the fatal shooting of an unarmed black teenager by police last month.

Police said that 17-year-old Laquan McDonald, who was carrying a BB gun, was shot while he was walking away from officers in the Bronx on May 31.

He was killed in a confrontation with police.

The NYPD did not release details about the shooting.

Chief of Department Anthony Batts has been leading the probe since May, saying that McDonald was shot at a distance from the officers, and that the officer who fired his gun did not have a duty to shoot McDonald.

The New Yorker’s Jeffrey Goldberg wrote Wednesday that the chief’s comments suggest that he is trying to paint the department as racist and a problem for minorities.

“If the chief thinks that Laquans death was an isolated incident, he’s not going to be held accountable for that,” he wrote.

He added that Batts did not address concerns about the use of force in the city.

The department has since fired four officers who were involved in the incident, including one officer who was accused of planting a false bomb in a subway station in March.

The chief has also announced that he will not be personally involved in whether the officers who shot McDonald will face any consequences.

He has said that he was following protocol in the case.

McDonald’s death sparked protests, and the city is now grappling with a new wave of protests over police killings of black men.