Jorge “Jinho” Ferreira feels the tension between being black and carrying a badge every day as a sheriff’s deputy in Alameda County, California.

“I feel like you have to prove yourself on every level,” said Ferreira, 39, who patrols about 30 miles east of San Francisco. “You have to prove yourself to the black community, you have to prove yourself to all of your co-workers, you have to prove yourself to society.”

With the nation roiled by two grand juries’ recent decisions not to indict white