Whites are killed at three times the rate of Blacks, but Blacks are a sixth of the population. So Blacks are killed at twice the rate of Whites when you factor in the relative sizes of their populations.
The following is from the Washington Post which has been keeping a database of police shootings since 2015.
Black Americans are killed at a much higher rate than White Americans
Although half of the people shot and killed by police are White, Black Americans are shot at a disproportionate rate. They account for less than 13 percent of the U.S. population, but are killed by police at more than twice the rate of White Americans.
https://www.washingtonpost.com/graphics/investigations/police-shootings-database/