(Reuters) - The father of a black teenager killed three years ago by St. Louis police has filed a wrongful death lawsuit alleging that an officer used excessive force in shooting his son in the back as he ran away from him and his partner.

FILE PHOTO: Dennis Ball-Bey, the father of Mansur Ball-Bey, stands in front of the steps where police shot his son as a photo of Mansur hangs on the fence in St. Louis, Missouri, U.S., August 20, 2015. REUTERS/Lawrence Bryant/File Photo

Dennis Ball-Bey filed the action against the city of St. Louis, its former police chief and two officers involved in the shooting death of Mansur Ball-Bey. The lawsuit, filed in federal court in St. Louis on Friday, seeks unspecified damages, court records showed.

The lawsuit alleged that the officers, both of them white, overreacted while chasing Mansur Ball-Bey, 18, on Aug. 19, 2015, when the teen was shot and killed. It added that Ball-Bey was not armed, despite police statements in 2015 that he pointed a gun at the two officers.

Mansur Ball-Bey, the lawsuit said, had committed no crime and that the two officers who fired at him, Ronald Vaughn and Kyle Chandler, were not in danger.

An autopsy found Ball-Bey died from a single gunshot that entered his back and struck his heart.

Two years ago, the top prosecuting attorney in St. Louis decided not to file charges against Chandler and Vaughn for the incident.

A spokesman for the St. Louis mayor’s office declined to comment on Monday, citing pending litigation. A police department spokeswoman deferred comment to the mayor’s office.

Previously, the attorney for the officers, Brian Millikan, said the shooting was a “tragedy but was absolutely justified,” the St. Louis Post-Dispatch reported. Millikan could not be reached immediately for comment.

Former St. Louis Police Chief Sam Dotson and the city were named as defendants in the legal action, which said that Ball-Bey’s death was a result of policies employed by the city and its police department.

Mansur Ball-Bey was employed at United Parcel Service, had no criminal record and was a youth leader at his church, added the lawsuit.

Dotson retired from the police department in 2017 and is now the director of security for the Washington Nationals Major League Baseball team.