Last weekend's fatal shooting of a plainclothes Baltimore police officer — by colleagues who mistook him for an assailant — has taught a stunned force the same hard lesson learned by other agencies whose officers made similar deadly mistakes.

In 27 cases across the country since 1980 in which police officers were mistakenly killed by other officers, all but one involved a victim who was not in uniform. Among them was last Sunday's shooting of Officer William H. Torbit Jr., an eight-year veteran of the Baltimore police force who was killed by fellow officers while trying to break up a rowdy crowd outside a club.

In most cases, police in other cities responded to the tragedies by ordering plainclothes officers back into uniform — as Baltimore did as an interim fix while reviews are under way — or to wear color-coded bandanas or jackets. Most launched investigations aimed not only at determining whether the shootings broke any laws, but also at instituting reforms...

Fatal police-on-police shootings spark reforms - baltimoresun.com