Trenton Mayor Tony Mack, his brother, Ralphiel, and convicted sex offender Joseph Giorgianni, are accused of conspiring to obstruct, delay and affect interstate commerce by extortion.
Federal prosecutors allege Mack agreed to use his influence in connection with a proposed parking garage project.
Court documents show federal agents began investigating Mack and the others in September 2010. They searched their homes in July of this year.
Authorities say the defendants received $54,000 and anticipated accepting another $65,000 from a cooperating witness who purported to be a developer.
The arrests took place Monday morning.
(Copyright 2012 by The Associated Press. All Rights Reserved.)