JUDY WOODRUFF:

The police department in Oakland, California, has a long and troubled history. The most recent scandal to roil the department involves alleged sexual misconduct by officers.

Police chief Sean Whent resigned last week for reportedly mishandling that situation. And there are decades of tension and mistrust between officers and the African-American community.

Stanford University has been studying that often volatile relationship, and the results of its groundbreaking study were released today.

Special correspondent Jackie Judd has our exclusive report.