Some New York City patrolmen say they're being harassed because they've challenged the police department's street stop tactics.

One officer says a rat sticker appeared on his police locker when he decided to testify at an ongoing civil rights case challenging the stops.

The NYPD has made 5 million stops in the past decade. A civil rights lawsuit contends illegal quotas are behind wrongful stops of black and Hispanic men.

The officers follow in a line of police whistle-blowers who have paid a price for testifying against their own. The most famous is Frank Serpico, whose story is etched in popular culture by the hit movie starring Al Pacino.

In an interview, Serpico says he tries to give comfort to the current crop of officers who have reported wrongdoing.