A lawsuit alleging "excessive and deadly force" has followed a homicide charge in the fatal police shooting of an unarmed black teenager in East Pittsburgh. "It is time that we begin to seek answers," a lawyer tells ABC News of the federal suit filed Tuesday on behalf of the parents of Antwon Rose. It alleges the department "failed to properly train, supervise, screen, discipline, transfer, counsel or otherwise control" its officers, including 30-year-old Michael Rosfeld. "Without issuing a verbal warning or attempting any pursuit," Rosfeld, who has since been charged with homicide, shot 17-year-old Rose in the back as he fled a June 19 traffic stop involving a car suspected in a drive-by shooting, the suit claims, per the Pittsburgh Tribune-Review. One of Rose's companions has been charged in relation to the drive-by. (More Antwon Rose stories.)