Four years ago, Eric Adams, fresh off what would become a razor-thin victory in the Democratic primary for mayor of New York City, held forth with characteristic bombast. He was the “face of the new Democratic Party,” he said.

He suggested that with his working-class roots and police background, he was the model of new leadership for a party held hostage by the gentrifying elite. He would orient City Hall toward the dispossessed and the underserved. And as the city’s second Black mayor, he would continue the legacy of the first, David N. Dinkins.

“I am you,” he told his supporters that November, after he won the general election. “The campaign was never, never, never about me.”

But as he began to lead New York City, Mr. Adams allowed his focus to become uncommonly inward-looking, oriented around the very few allies he considered sufficiently loyal.

Questions arose early on about his character, job performance and decision-making. He was caught lying about what he ate and with whom he owned real estate. And investigations plagued his administration, finally landing at the mayor’s door.

Federal prosecutors charged Mr. Adams with bribery and fraud, saying he accepted free and heavily discounted travel on Turkish Airlines in exchange for help opening a new Turkish consulate in Manhattan that the Fire Department had deemed unsafe. Prosecutors accused him of knowingly soliciting illegal foreign donations that were routed through straw donors.