Over the past year we've seen all sorts of stories about black men (armed and unarmed) being killed by police officers. Most recently, Vyan posted a diary with statistics showing that officers overwhelmingly killed blacks over whites.. (I calculated that a random black person in New York was 23 times more likely to be killed by a police officer than a randomly picked white)
Now one explanation for this happening would be that police officers are scared that they're more likely to be killed by a black citizen than a white one, so I went searching the FBI crime database. They keep meticulous records of Officers killed in the line of duty. I wanted to see what the actual stats were about officers murdered on the job.
With some further processing of the FBI data and it turns out that, from 2004 to 2013 (inclusive) 51% of police officers killed by identified assailants were murdered by white offenders and only 43% were killed by blacks. This is despite the fact that (as I remember) almost 60% of police interactions are with blacks.
That's right -- police interactions with whites are a good bit more dangerous than intractions with blacks but it's overwhelmingly blacks who are killed by police. Prejudice maybe?