Investigators accused the city’s cash-strapped top prosecutor of repeatedly selling his influence and offering to intervene in a case on behalf of one wealthy benefactor. In exchange, they said, Williams accepted luxury trips to foreign locales, a used Jaguar convertible, and other gifts including a $205 Louis Vuitton necktie and a Burberry watch.

When that was not enough to cover the costs of his lush life, Williams allegedly resorted to stealing from his own mother, draining more than $20,000 of Social Security and pension income intended to pay for her nursing home to cover his mortgage and electricity bills.

“The alleged misconduct … is brazen and wide-ranging, as is the idea that a district attorney would so cavalierly trade on elected office for financial gain,” FBI Special Agent-in-Charge Michael Harpster said at an afternoon news conference announcing the charges. “The immense authority vested to law enforcement has to be kept in check, and that requires decision-makers and leaders with a steady ethical compass.”

The criminal case brought to a head rumors that have dogged Williams for years and put a damning footnote on his eight-year career in office, which began in 2010 with accolades for sweeping changes he promised to implement within the city’s justice system, only to be overshadowed more recently by a series of scandals.

As he announced his decision last month to forgo a reelection bid, Williams, 50, apologized for bringing “embarrassment and shame” to the District Attorney’s Office through repeated ethical lapses and vowed to win back the trust of the public and his employees.

But hours after Tuesday’s indictment, Williams offered no indication whether he now intended to resign. His lawyer, Michael Diamondstein, vowed that Williams would fight the charges in court.

“Mr. Williams vehemently denies that he ever compromised any investigation, case, or law enforcement function,” he said.

Sources familiar with the course of the investigation said Williams rejected a plea deal from prosecutors earlier this week. He spent the day at home with his family, an office spokesman said, and was expected to surrender and be arraigned Wednesday afternoon.

Inside Williams’ office of 300 prosecutors, the allegations hit like a bomb. In an internal memo, his top deputy, Kathleen Martin, assured the staff that the office was cooperating with the investigation and that no other employees had been accused of wrongdoing.

“I understand and appreciate that you may be angry and frustrated with the unwanted spotlight placed upon our office, emotions that you are certainly justified in feeling,” she wrote.

Outside, the city’s political and legal leaders offered swift condemnation.

Mayor Kenney called Williams’ alleged actions “deeply shameful” and a “flagrant violation of the law.”

“At a time when our citizens’ trust in government is at an all-time low, it is disheartening to see yet another elected official give the public a reason not to trust us,” the mayor said in a statement. “That this comes at the head of our justice system is even more troubling.”

Deborah R. Gross, chancellor of the Philadelphia Bar Association, called for Williams to step aside immediately.

“The charges against him cast a shadow on the District Attorney’s Office, our legal community, and the entire City of Philadelphia. It truly is an embarrassment,” she said.

The case against Williams, which involves charges of honest services fraud and other bribery-related counts, hardly came as a surprise.

...

Williams’ prosecution is being handled by the U.S. Attorney’s Office for New Jersey, after Justice Department officials in Philadelphia recused themselves because of their frequent collaboration with the District Attorney’s Office.