by Dennis Cauchon

About the author: Dennis Cauchon is a staff reporter for USA Today newspaper.

Jose Sierra Jr. points to a scar on his forehead. A cop from the 70th Precinct put it there in 1994, he says. Sierra was drinking a beer and playing dominoes with his buddies in front of Jimenez Spanish Grocery in the Flatbush section of Brooklyn, New York, when the cop told him not to drink in public.

One word led to another, and Sierra found himself in the back of a police car having a police radio smashed into his face.

“‘Go ahead, file a complaint, you low-life Puerto Rican,’” he says the cop told him. “‘Every time we see you, we’ll f--- with you.’”

Sierra filed a complaint, he says...