In explaining the lack of blacks in their ranks, police chiefs say they have few openings and even fewer African American applicants; when blacks do apply, the chiefs say, they don't score well enough on civil-service tests.
Yet many of these obstacles appear to melt away when blacks obtain political power.
In 1998, Jacqueline B. Mosley became the first African American mayor of Yeadon, a town with an 80-percent-black population. Yeadon then had two black officers on a force of 15.
A retired Philadelphia public school teacher, Mosley threw herself into the hiring process, interviewing police candidates.
"I spoke to the chief. He used to do all the screening. I said it can't be that way," Mosley said.
Now the department has six blacks and seven whites.
"People have to be concerned about it," she said. "And for years, they haven't been."
The encounter took place minutes after the two childhood friends, both Liberian immigrants, bumped into each other on Main Street in September 2004.
Wamah and Bedell hardly looked liked drug dealers or thugs.
Wamah, 53, a photographer for a Philadelphia public-relations firm, was dressed in slacks and dress shirt. He was headed for an appointment with a physical therapist. Bedell, 46, is a home remodeler with real estate in Philadelphia and Delaware County.
But that didn't count for much when police ordered them to leave.
When Bedell protested that they had done nothing wrong, both men were arrested, searched, and charged with disorderly conduct, Wamah said. Neither man has had any other arrests.
Wamah, a U.S. citizen for the last 16 years, said one of the officers gave him a chilling piece of advice: "If you don't like it, go back to where you came from."
After a judge dismissed the charges against both men, Wamah filed a federal civil-rights lawsuit, charging that he was unlawfully searched, then roughed up on the street during his arrest. The town has denied wrongdoing.
Wamah sees his experience as a cautionary tale in an increasingly black town with a nearly all-white police force determined to take a hard line, even if it meant arresting two middle-class, middle-aged black men chatting on Main Street. And it's been hard to put behind him.
"When I see the cops in Darby," Wamah said, "I'm very paranoid."
