The Illinois Fraternal Order of Police has suspended the head of Chicago’s police union, one day after he accused fellow union leaders of scheming with City Hall and arbitrators to “fix” police contracts.

Chicago FOP Lodge 7 President Michael Shields was apparently suspended during a union meeting Tuesday night. On Monday, Shields sent a letter to the city’s inspector general accusing four current and past union leaders of colluding with independent arbitrators and city negotiators to hold contract arbitrations that were “manipulated and phony.”

The letter was first reported by the Chicago Sun-Times, and later leaked to other media outlets, including WBEZ.

“As many of you are aware, this past Monday, Lodge President Michael K. Shields publicly accused respected arbitrators, City and FOP labor lawyers, and present and former Lodge officials of fraud and conspiracy to commit fraud during past contract negotiations,” reads a statement on the Chicago union’s website.

“Due to the recent actions of President Shields, Illinois State FOP Lodge President Ted Street was forced to suspend President Shields’ ‘membership rights, duties and authority and therefore is suspended as President of Chicago FOP Lodge #7,’ pending a hearing before the State Lodge Board of Trustees,” the statement reads.

Street did not return phone calls seeking further details.

Tuesday night’s police union meeting was apparently tense enough that someone called the police to keep the peace.

“After a call for service was received, a sergeant and two officers were dispatched to the scene to ensure that order and safety was maintained, but, at no point, did CPD interfere with the business of the union,” Chicago Police Department spokesman Adam Collins said.

In an interview with WBEZ earlier on Wednesday, Shields denied that he had been suspended and maintained he was still acting as president of the Chicago FOP lodge.

“I brought to light information to the inspector general regarding past practices of [former President] Mark Donohue, [First Vice President] Bill Dougherty, [Financial Secretary] Rich Aguilar and [former Third Vice President] Greg Bella,” Shields told WBEZ, referring the the four union leaders he accused of rigging contracts. “Now [they] are retaliating against me by having their close friend, Ted Street,  attempt to take action against me, which is 100 percent illegal and the truth will come out about those four.”

Despite Shields’ earlier claim that he was still in charge, the statement from the Illinois FOP later Wednesday afternoon said Dougherty will serve as acting union president.

Contract arbitrations occur when one side in a negotiation declares an impasse. Outside arbitrators are supposed to mediate the dispute as an independent third party, then issue a legally binding decision.

But in Monday’s letter to Chicago Inspector General Joe Ferguson, Shields claimed the four union leaders “rigged” at least two contract arbitrations in order to gain “political cover against FOP members’ potential accusations that the FOP leadership had ‘sold out’ to the City of Chicago.” He also claimed the head of the police sergeants’ union played ball with City Hall during “phony” contract talks.

Shields did not cite any specific evidence to back up his claims in the letter, or during later interviews with WBEZ. He said he was told of the schemes by the union’s top lawyer, Paul Geiger. Geiger did not return phone calls seeking comment.

The police union’s public flap comes just a few months before Shields was to stand for re-election as lodge president. He’s taken heat this year for missing two deadlines that could cost rank-and-file cops their retroactive pay raises, as the union continues to negotiate a new contract with the city.

Aguilar denied the accusations in the letter were true. The head of the Chicago Police Sergeants’ Association, Jim Ade, said Shields’ claims were “baseless.” Bella, Dougherty and Donahue did not return phone calls from WBEZ.

Alex Keefe covers politics for WBEZ. Follow him on Twitter @akeefe.