He still has not been identified.
Update 4 p.m. ET: The family of Antwon Rose has hired civil rights Attorney Lee Merritt to represent them. Merritt has previously represented the victims of violence in Charlottesville and several cases related to the Black Lives Matter movement.
Update 2:53 p.m. ET: Rose was shot three times while running from police, said Coleman McDonough, superintendent of the Allegheny County Police Department.
McDonough said two guns were found in the car after the traffic stop, but Rose was not armed at the time of the shooting. The driver of the vehicle was initially detained by police. He has since been released, police said.
A third person who was in the vehicle and fled has not been located.
The East Pittsburgh police officer involved in the shooting has been placed on administrative leave.
Pittsburgh Mayor William Peduto released the following statement:
“Any loss of life is tragic, and especially the loss of life of a child. This is a devastating situation and I am saddened for Antwon Rose and his family.
“While Tuesday's shooting was not within the city's official borders it impacts all of us in the Pittsburgh region, and particularly those in the African American community. In my reactions to the incident I should have acknowledged that these shootings affect all of us, no matter where we live, and for that I am sorry.
“Tuesday night I was receiving numerous calls and messages asking me to respond to the involvement of police in a shooting in East Pittsburgh borough, and at the time I was attempting to clarify for the national public that the City of Pittsburgh Bureau of Police, which I ultimately oversee, were not involved.”
According to the Allegheny County Police Department, Rose got out of a vehicle that matched the description of a vehicle seen near a shooting that occurred shortly before 8:30 a.m. on Kirkpatrick Avenue in North Braddock.
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The vehicle, which police said had damage from bullets to the back window, was stopped near Grandview Avenue and Howard Street.
An officer from the East Pittsburgh Police Department was handcuffing the driver when two males ran from the car, police said. One of those males was Rose, according to officials.
Rose was taken to McKeesport Hospital, where he was pronounced dead.
The Allegheny County Police Department is asking the other person who ran away from the vehicle to turn himself in "so that he can give a comprehensive description of what occurred."
The victim in the North Braddock shooting, a 22-year-old man, was treated for his injuries and released from an area trauma center.
The Allegheny County Police Homicide Unit is investigating both incidents.