It's happened before

Note: The Times doesn't mention the ethnicity of either officer until the seventh paragaph

NY Times, 2009 -  A New York City police officer who had just gotten off duty was fatally shot late Thursday in East Harlem by a fellow officer who mistook him for an armed criminal, Police Commissioner Raymond W. Kelly said.

The officer who was killed, Omar J. Edwards, 25, a two-year veteran who was assigned to patrol housing projects and was wearing plain clothes, was shot in the arm and chest after a team of three other plainclothes officers in a car came upon him chasing a man on East 125th Street between First and Second Avenues with his gun drawn, Mr. Kelly said.

The team’s members, assigned to the anti-crime unit in the 25th Precinct, got out of their vehicle and confronted Officer Edwards. The police were investigating whether the officers had identified themselves or demanded that Officer Edwards drop his weapon before one of them opened fire.

Mr. Kelly identified the officer who fired the shots only as a four-year veteran of the department, and said he had fired six rounds from his 9-millimeter Glock. Two bullets struck Officer Edwards.

Officer Edwards, a recently married father of two from Brooklyn, was taken to Harlem Hospital Center, where he was pronounced dead at 11:21 p.m. No one else was injured.

"While we don’t know all of the details of what happened tonight, this is a tragedy,” Mayor Michael R. Bloomberg said during an early morning news conference at the hospital. “Rest assured we will find out exactly what happened here and see what we can learn from it so it can never happen again.”

The shooting is likely to raise questions again about departmental procedures involving communications among plainclothes officers — particularly those in different units — as well as issues of race. Officer Edwards was black; the officer who shot him was white.