You can try the CDC and the FBI crime statistics and try to cross reference it to a time period and cross reference between killed by police and killed by same race.
Unfortunately you will have to also do comparisons over different time periods and that is not precise but might give you a base to work from.
Sorry, to see something like this is never easy to do the difficult part is trying to remain unbiased and let the data speak and not let your personal beliefs and wants manipulate the Data.
Good Luck

you can go to the DOJ website where all of those statistics are recorded. If you know how to research a database you will find a breakdown of crime statistics in every imaginable demographic commutation. Black on Black, Black on White, White on Black, Male on Female, Female on Male...rape, robbery, murder, theft, arrests, convictions...it's all there if you know how to extract the information you are seeking.

The official FBI crime statistics are usually published a couple of years behind.