New York City Mayor Bill de Blasio is scheduled to be questioned on Friday by federal prosecutors in connection with a corruption investigation into fundraising. The investigation encompasses fundraising by the mayor's campaign and a related nonprofit he set up. De Blasio agreed to do the interview earlier this year and it will be conducted by prosecutors from the office of Manhattan U.S. Attorney Preet Bharara. De Blasio has maintained that he and his aides have done nothing wrong. The investigation seeks to determine whether donors to his 2013 mayoral campaign received special favors for their contributions.