Seth Williams vows toughness, but mercy: Sworn in as first black district attorney in Pennsylvania

"Four years from now, when I stand before you again," Williams told an inaugural audience at the Kimmel Center, "we will not have the lowest conviction rate in America."

Williams warmly acknowledged his predecessor, Lynne Abraham, who yesterday finished 19 years in the district attorney's post and said that she may soon plot another run for elected office.

"I'm going to work for a law firm, then down the road probably make an announcement for another office," Abraham told reporters.

Abraham declined to identify the office she might seek, but her longtime political adviser, Eleanor Dezzi, said yesterday that her potential run would be statewide.

"A lot of people have been approaching her about running for attorney general," Dezzi said in a telephone interview. "She's considering it."