Mel Evans / AP file In this July 7, 2011 file photo, Trenton Mayor Tony Mack listens to a question in Trenton, N.J. He was arrested Monday in connection with a corruption probe.

Updated at 3:10 p.m. ET: Federal authorities arrested Trenton, N.J., Mayor Tony Mack and more than half a dozen other people early Monday in connection with an ongoing corruption probe, NBC 4 New York has learned.

Joseph "JoJo" Giorgianni, a top campaign contributor, and six others were also taken into custody. Specific charges against the suspects are expected to be outlined by Paul Fishman, the U.S. Attorney for New Jersey, later Monday.

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Mack and the others arrested Monday were brought to the FBI office in Hamilton for processing and are scheduled to appear in federal court.

A federal magistrate on Monday ordered Mack released on $150,000 bond provided he not leave the state while free on bail, The Associated Press reported.

The arrests are the latest development in an ongoing federal investigation into alleged corruption within Mack's administration, which has been marked by accusations of nepotism and reckless spending. In July, FBI agents searched offices in Trenton City Hall a day after raiding the mayor's home. They also searched the home of his brother, Ralpiel Mack, and that of Giorgianni.

Mack's administration has been in turmoil from Day 1, staggering from one crisis to another. A housecleaning of staff at City Hall opened the door for Mack's own appointees, who quickly turned it into a revolving door. Some left over questions about their credentials, others to face criminal charges.

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In Mack's first year in office in Trenton, a city of 85,000, he ran through a string of business administrators. The first resigned after a month, saying the mayor didn't believe in "good government." Another resigned just ahead of pleading guilty to embezzlement at another job.

Mack's housing director quit after it emerged that he had a theft conviction. His chief of staff was arrested trying to buy heroin. His half-brother, whose authority he elevated at the city water plant, was arrested on charges of stealing.

Questions have also been raised about how he financed his campaign for mayor.

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A former longtime city employee sued the mayor late last year. The parks department employee said she was let go after refusing to dole out jobs for the mayor's friends, refusing to give federal grant money to people who didn't apply and for inquiring about city funds she said were missing.

The ex-employee also said she was replaced by a Mack supporter who never showed up for his $40,000-a-year job.

A former campaign aide told NBC 4 New York he disassociated with Mack when he "saw the way he was going."

"This is not a surprise," Jerell Blakley said of the probe into Mack's activities. "A lot of people in Trenton were of the opinion -- not of if, but when."

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