Federal authorities investigating union tactics in Greater Boston are looking into whether a member of Mayor Martin J. Walsh’s administration warned a popular music festival it could face problems if it did not hire union members, according to people familiar with the investigation.
The warning to the Boston Calling festival allegedly came from Kenneth Brissette, the city’s director of tourism, sports, and entertainment, in 2014, the people said.
Brissette acknowledged last year as part of a city investigation that he warned two restaurants of possible union pickets connected to a nonunion television production of the reality show “Top Chef.’’ The investigation concluded he had done nothing unlawful.
In a statement issued Friday night in response to Globe questions, the Walsh administration confirmed that federal authorities have sought information about the music festival. The statement did not provide details about the investigation or address the alleged involvement of Brissette.
“There have been questions by investigators about Boston Calling, an event that has been hosted on City Hall Plaza since 2013, that are similar to the questions raised about ‘Top Chef,’ ” Walsh’s spokeswoman, Laura Oggeri, said in a statement.
“The city’s Law Department had asked attorney Brian Kelly to take a look at the event in its entirety, as well as more recently the Office of Tourism, Sports, and Entertainment to ensure that the proper policies and procedures are in place,” she said.
At issue in the FBI’s investigation is whether Brissette merely alerted Boston Calling to a potential problem with organized labor, or attempted to pressure festival organizers to hire union stagehands, according to one of the people familiar with the inquiry.
The inquiry highlights a longstanding debate about where the line falls between forceful advocacy on behalf of working people and unlawful coercion — one of the central questions in what has become a broader investigation of local union tactics that reaches into City Hall.
Brissette, reached Friday by phone, said, “You have to talk to legal and the press office.” Efforts to reach Brissette’s lawyer were unsuccessful.
In the previous incident, both restaurants pulled out of the “Top Chef’’ shoot after Brissette’s warnings, according to the city’s investigation, performed for Walsh by Kelly, a partner at Nixon Peabody. Kelly said in a report that the restaurateurs contacted by Brissette considered the warnings a friendly heads up, and not threatening.
The report, issued last December, said that Brissette had not colluded with the Teamsters. Brissette kept his job and was not disciplined. Kelly declined to comment Friday on whether he has reviewed allegations involving Brissette and Boston Calling.
“That’s a separate matter and it would be premature for me to comment on it at this time,” Kelly said.
The “Top Chef’’ case has already resulted in federal indictments against five Teamsters members for allegedly harassing and trying to extort the nonunion TV crew. Those prosecutions are pending.
The Boston Calling investigation involves the International Alliance of Theatrical Stage Employees, Local 11, which did not respond Friday for comment. A reporter visited the union’s office on Old Colony Avenue in South Boston and left a message on the voice mail of the organization’s business manager, Colleen A. Glynn.
The FBI declined to comment on Boston Calling. Festival cofounder Brian Appel also declined by e-mail to comment. Boston Calling started on City Hall Plaza in 2013. The three-day festival, which occurs twice a year, is next due to run the weekend of May 27.
On Thursday, Walsh announced a review of Tourism, Sports, and Entertainment, the office Brissett leads, “to make sure that our agencies and staff have the right training and tools.”
“My intent is to build on what we learned from the review that attorney Brian Kelly conducted of interactions and permitting procedures related to the filming of ‘Top Chef’ in Boston,” Walsh said in a statement Thursday that did not mention Boston Calling.
“That report on ‘Top Chef’ brought transparency to how the city interacted with that particular production and I want to make sure that we build on that knowledge, learn from it and are using best practices in this field,” he said
The Walsh administration has refused to release text messages and phone records Kelly cited in his report.
The Globe has requested these records under the state public records act. In denying the request, the administration wrote that a report detailing a search of city employees’ text messages was secret because of an “ongoing internal review.”
Phone records used in the investigation also are secret, the administration claims, because even though Kelly was paid from public funds, he was not a city employee.
The Globe reported Sunday that Walsh, the former head of the Boston Building Trades, had been drawn into a sweeping federal investigation into union tactics in Greater Boston, and that he had been recorded on a court-authorized wiretap in 2012, before he was mayor, telling a developer it needed to use union labor in Somerville or it would experience permit problems on another project in Boston.
Walsh has adamantly insisted that he never threatened any developer, and has not been contacted by federal authorities in the investigation into tactics by the construction trades. On an appearance Friday on “Boston Public Radio,’’ Walsh would not say whether he had appeared before a grand jury related to “Top Chef.’’
“I’m not going to answer any of those questions right now because there’s an investigation,” Walsh told host Jim Braude, adding: “That case is going to continue to move forward. I’m going to wait until that case is finalized. I don’t want to compromise it.”