VIDEO:Off-Duty St. Louis Officer Kills Man in Gunfight, Triggering Angry Protests

An off-duty St. Louis police officer shot and killed a young African-American man Wednesday night in south St. Louis, triggering hours of protests. Police say the man fired on the off-duty officer. The officer was not hit.

St. Louis Police Chief Sam Dotson told the St. Louis Post-Dispatch the officer was working a secondary job for a private security company at the time of the shooting.

Relatives of the suspect who came to the scene said the victim had been unarmed. They identified him as Vonderrit Myers Jr., 18.

Teyonna Myers, 23, of Florissant, said Myers was her cousin. "He was unarmed," she said. 'He had a sandwich in his hand, and they thought it was a gun. It's like Michael Brown all over again."

Dotson said the officer had been in a car when he saw three males in the 4100 block of Shaw Boulevard at about 7:30 p.m. Wednesday. One of the males started to run away but stopped. The officer did a U-turn and then all three ran. The officer drove through streets following them, and then he got out and chased them on foot.

Assistant Police Chief Alfred Adkins said the teen the officer was chasing jumped from some bushes and struggled with the officer.

The man had a gun and fired at least three shots at the officer, who returned fire, the chief said. The man attempted to fire more but his gun jammed, Dotson said. Police said they recovered a 9mm Ruger.

The officer fired 17 times, he said. It is unclear how many times the teenager was struck.