The recently appointed business administrator of New Jersey's capital city has taken the helm at Trenton City Hall amid an FBI investigation of the mayor.

Employees at City Hall said Friday that Sam Hutchinson is now serving as acting mayor of the city of 85,000, in place of Tony Mack.

Mack on Thursday sent a letter to the city clerk designating Hutchinson as acting mayor when he is unavailable. City employees were unable to provide information about Mack's whereabouts.

FBI agents raided City Hall on Thursday, a day after searching the home of Mack, his brother and a campaign donor.

Mack's two years in office have been marked by accusations of cronyism and mismanagement. His only public comment has been to say that he has not violated the public trust.

(Copyright 2012 by The Associated Press. All Rights Reserved.)