TRENTON, N.J. - Federal authorities turned to a familiar method to build their case against Trenton Mayor Tony Mack: They used a government informant to try to bribe a public official over a fake land-development deal.

Mack, his brother Ralphiel and convicted sex offender Joseph Giorgianni, a Mack supporter who owns a Trenton sandwich shop, were each accused Monday of a single charge of conspiring to extort the undercover informants who pulled them into the scheme.

The plan to turn a downtown Trenton lot into a parking garage was concocted solely for the bust. Officials said there was no intent to put up the garage. At a news conference Monday, U.S. Attorney Paul Fishman joked that he didn't know whether there was a shortage of parking in the area.

The case has echoes of "Bid Rig," a massive New Jersey corruption case that netted 46 arrests three years ago.

In that case, Solomon Dwek, a disgraced real estate speculator and admitted Ponzi schemer, agreed to wear a wire for the government in a plea deal after his arrest in a $50 million bank fraud.

While most of those implicated were convicted, the government's case was not a slam-dunk against each of them.

About three-quarters of the defendants pleaded guilty. But two were acquitted by jurors and four had charges dropped by a judge.

Authorities have not named the two informants who were at the heart of the Mack case, but said that one was cooperating to try to get a better deal in his own criminal case while the other was paid.

Court filings said the city-owned land for the garage was assessed at $271,000, but that Mack, a 46-year-old Democrat, and Giorgianni agreed to take $100,000 for it along with a $100,000 bribe that they would split.

Authorities said that in all, the men were paid $54,000 and promised another $65,000.

Mack's lawyer, Mark Davis, said he believes his client is innocent, as the mayor has professed since his home was raided in July. "I believe that the evidence, as far as I can tell, appears to be insufficient to prove the charge," he told The Associated Press.

John Hartmann, the lawyer for Ralphiel Mack, said his client is also innocent and called the government's case against him "weak."

The criminal complaint portrays Giorgianni as a boastful man who did most of the talking with two FBI informants, making Mack sound eager to accept bribes.

Authorities said that at one point, he was caught on tape saying, "One thing about the Mack administration — when I say that, it's me and Mack — we're not greedy. We're corruptible. We want anybody to make a buck," and "I'm there to buffer the thing where, you know, take the weight ... going to jail's my business. It ain't his."

Giorgianni's public defender did not return a call to the AP on Monday.

All three defendants were released Monday on bail.

Tony and Ralphiel Mack, the football coach at Trenton Central High School, each face 20 years in prison if convicted.

Giorgianni is also charged with running an oxycodone distribution network and a weapons charge and faces up to 50 years in prison.