CTNJ file photo

House Republican Chief of Staff George Gallo resigned after concluding that he is a person of interest in a federal investigation of the caucus’ campaign vendor mailings, which has seen subpoenas served at Republican offices in the Legislative Office Building.

House Minority Leader Lawrence Cafero issued a written statement on the investigation and Gallo’s resignation Thursday afternoon a day after many GOP lawmakers were questioned by FBI agents.

“Yesterday the FBI came to the LOB to interview various members of our caucus relating to an inquiry into campaign vendor mailings,” Cafero said. “Our caucus is cooperating fully with the federal inquiry into House Republican activities.”

Cafero said Gallo resigned Thursday after offering his opinion that he is a person of interest in the feds’ investigation.

“As such, he indicated that he did not want to cause unwarranted distractions to the caucus that would take away from their legislative duties. For that reason, and for personal family considerations, he tendered his resignation and it was accepted, effective at midnight tonight,” Cafero said. “George has served as House Republican caucus honorably and with the highest level of professional standards since 2007. He will be missed.”

Gallo did not return calls for comment. Thomas Carson, spokesman for Connecticut’s U.S. Attorney Deidre Daly, declined comment Thursday on the investigation.

Cafero said that FBI agents asked that lawmakers “refrain from divulging the details to the investigation to the public and press” to the extent that they were aware of them. And lawmakers were hesitant to talk about it Thursday.

“They talked to a lot of people. So we’ll see,” Rep. Gail Lavielle, R-Wilton, said.

Sources say federal investigators were asking about Direct Mail Systems of Clearwater, Florida, which handles the campaigns of several Republican lawmakers. Sources said they wanted to know if they were steered to the company, which is headed by Michael Milligan, a veteran Republican fundraiser.

Milligan did not return calls for comment.

Since 2008, Connecticut Republican candidates, Republican Town Committees, PACs, and the Republican House Campaign Committee have spent nearly $2 million with Direct Mail Systems, according to State Election Enforcement Commission filings.

Gallo, who headed the state Republican Party between 2005 and 2007, was in charge of running the House Republican caucus campaigns through the House Republican Campaign Committee apparatus. He owns a consulting company called Vinco Group, which was paid over the years by various Republican PACs.

The focus of the investigation is unclear, but former state Rep. Kevin Rennie was the first to report the presence of federal investigators in the state office building on his blog.

This isn’t the first time the House Republican caucus has found itself involved in a federal investigation. In June 2012, federal investigators informed Cafero that five straw donors contributed to Republican PACs.

Cafero promptly returned the checks. Then during the trial of Robert Braddock Jr., the finance director for former House Speaker Chris Donovan’s Congressional campaign, federal prosecutors showed undercover video of an informant attempting to put $5,000 in cash in his fridge in the Legislative Office Building after a meeting. Cafero was never charged by federal authorities.

Direct Mail Systems is one of a dozen national direct mail companies that does business in Connecticut.

Tom Foley, who is seeking the Republican gubernatorial nomination, said he used the company briefly in 2010.

“They didn’t perform very well so we stopped using them,” he said Thursday.