Former Gov. David Paterson, who had endorsed his successor, Andrew Cuomo, in the Democratic primary, said he believed Mr. Adams “would run the city the best.”

Erden Arkan, 76, pleaded guilty in January to conspiracy to commit wire fraud through the collection of straw-man campaign contributions. He agreed at the time to cooperate in the government’s prosecution of Adams, which was dropped in April, a move that triggered upheaval within President Donald Trump’s Justice Department.