Here are some facts taken from a project being run by the Guardian and cited by James Comey as being far more accurate than the volunteer reporting of police homicides submitted to the FBI.  It is a compilation of all known police killings in 2016:

"Black males aged 15-34 were nine times more likely than other Americans to be killed by law enforcement officers last year, according to data collected for The Counted, an effort by the Guardian to record every such death. They were also killed at four times the rate of young white men."

Native Americans were also killed at a much higher rate than white males.  The saddest part to me was that one in five police killings involved a mentally ill person of any color or age.

https://www.theguardian.com/us-news/2017/jan/08/the-counted-police-killings-2016-young-black-men