Hundreds of people gathered at Philadelphia's Sheet Metal Workers Union on this sunny Labor Day morning to show solidarity and strength before marching in the city's Labor Day Parade.

But for some, federal and state investigations into one of Philadelphia's top labor leaders overshadowed the event.

At around 9:30 a.m., Patrick Eiding, president of the AFL-CIO in Philadelphia, got a crowd of union members revved up, giving props to the nice weather and taking a jab at federal authorities. 

"The FBI's not here, so we're okay, I think," Eiding said. "Stay over there! Get some of them bad guys! Leave people alone who are doing something for working people!"

Eiding is referring to the FBI's investigation of John Dougherty, who heads the International Brotherhood of Electrical Workers Local Union 98 and is widely considered the city's most influential labor leader.

Over the last month, the federal agency has raided Dougherty's home, the office of a councilman, and union offices throughout the city. It's part of an investigation into the union's operations.

This isn't Dougherty's first brush with the FBI. The agency investigated him and the head of an electrical contractor in 2006. But the labor leader wasn't charged.

Earlier this year, the state launched an unrelated investigation into the electrician's union.

Eiding said many labor leaders in the city feel like, "here they come again." 

"They're constantly, always, constantly trying to find out something we're doing wrong, and all we do is represent workers," he said.

Nearby, Henry Nicholas, president of the National Union of Hospital and Health Care Employees, said the investigation was just politics as usual and that he's focused on another issue. "We are committed to make sure that we elect a Democrat to the White House in November," Nicholas said. "The vote is the only thing that counts."

Mayor Jim Kenney, who was elected with the support of the electrician's union, wouldn't comment on the investigation today, saying he wasn't going to let it impact the Labor Day celebration. Dougherty marched in the parade, but he wasn't available for an interview beforehand. The union's press spokesman, Frank Keel, later told NewsWorks in an email that Dougherty "cannot and will not discuss the investigations."

Update 9/6/15: This story has been updated to include a response from Local 98's spokesman.