Boston Mayor Marty Walsh on Friday said City Hall would "work with" federal prosecutors pursuing extortion charges against members of Teamsters Local 25, which is headquartered in Charlestown.

The federal indictment dated Sept. 29 alleges that a representative of the city alerted the Omni Parker House and the restaurant Menton that union members were planning to picket a reality television show that planned to film there, reportedly Top Chef.

"I'm concerned about the allegations that are out there. That certainly bothers me, because as a former labor official, never condoned those actions," Walsh, the former head of the Boston Building Trades, told reporters. He said he "absolutely" did not warn anyone to call the establishments.

After Omni Parker decided not to permit the filming at its location and the production group moved to a restaurant in Milton, federal prosecutors claim the five defendants barged in to the film production area of the Milton venue, chest-bumped crew members and made threats and racial and homophobic insults.

Walsh reportedly hired attorney Brian Kelly, a former federal prosecutor, to investigate the matter. Walsh said the city brought in outside counsel "so we can work with the United States attorney's office on anything they might need moving forward."

The mayor declined to comment on whether he would push the Teamsters to address the behavior of its members.

"There's a lot of men and women who work for the Teamsters union and other unions who do a lot of good things," Walsh said after an event at the Wentworth Institute of Technology.

Congressman Stephen Lynch, a South Boston Democrat and former ironworkers union official, said the charges recall an earlier era.

"What it sounds like is stuff that used to happen in the 40s and 50s and in today's labor movement there's no room for that," Lynch said. He said the area's labor movement is strong, and said, "I don't think that the actions of a couple people should reflect on those efforts."

Calling the alleged crime a "rarity," Lynch also said Walsh had a completely different style at the Building Trades where he was the "modern face of the labor movement" seeking collaboration not confrontation with businesses.

"That was never his style ever. He was always a gentleman," Lynch said.

State Republican Party officials on Wednesday called on Democratic officeholders to return any campaign contributions from Teamsters Local 25 in light of the indictments, singling out Attorney General Maura Healey, who received $500 from Teamsters Local 25 earlier this year, according to the Office of Campaign and Political Finance.

MassGOP also called on Healey to return a $15,000 contribution the union made to her campaign in on Aug. 27, 2014. But OCPF records show that the Healey campaign returned the entirety of that contribution on Sept. 5, 2014.

A Healey campaign spokesman said Wednesday that she does not plan to return the $500 the union donated this year. "Maura is pleased to have the support of Teamsters Local 25 and is pleased and thrilled to work with the hard working men and women in their organization," David Guarino said. "The allegations against five individuals who work and are members of the union should not be taken as a commentary on the entire membership of Local 25."