I don't know how this quote helps the argument
Scroll to the bottom of the collection of citations and you'll find this blockquote:

Nearly two times a week in the United States, a white police officer killed a black person during a seven-year period ending in 2012, according to the most recent accounts of justifiable homicide reported to the FBI.

On average, there were 96 such incidents among at least 400 police killings each year that were reported to the FBI by local police. The numbers appear to show that the shooting of a black teenager in Ferguson, Mo., last Saturday was not an isolated event in American policing.
"96 incidents out of at least 400 killings" seems to show that more than 75% of victims of police killings were white. I don't know what percentage of the US population is "black", but without that sort of information the statistics quoted are pointless.