As a business development team, the "Shadow Crew" was effective, federal prosecutors said:

One nighttime visit from the crew, and nonunion contractors reluctant to hire union ironworkers would change their minds and hire a few.

Maybe, as charged in a superseding federal indictment released Wednesday, they were convinced by beatings, arson, and vandalism.

Particularly persuasive, the indictment said, were anchor bolts smashed with sledgehammers and cranes that suddenly didn't work, along with the resulting costs and delays.

"I just want to thank the Shadow Crew for another job well done," a union business agent reported at a general meeting of Ironworkers Local 401 in February 2012, according to the indictment handed up by the U.S. Attorney's Office in Philadelphia.

A construction site in Malvern was "shut down for about a week and cost them $150,000," the business agent allegedly reported. The upshot? A week later, the agent got a call from the contractor, who decided to hire some union ironworkers.

Except for some new examples, the charges in Wednesday's superseding indictment repeat those included in a 47-page racketeering indictment returned in February, naming Joseph Dougherty, longtime head of the Philadelphia local, along with nine union officials, business agents, and members.

All have pleaded not guilty.

"While unions have the right to legally advocate on behalf of their members, my office will not tolerate the conduct of those who use violence to further union goals," U.S. Attorney Zane David Memeger said at a news conference announcing the arrests Feb. 18.

Since then, the local has been taken over by the union's national organization, with New Jersey Senate President Stephen M. Sweeney, a union ironworker and national union leader, now in charge of the troubled Philadelphia local.

"Local 401 was disheartened to read about the additional charges against the former officers and members," Sweeney said in a statement drafted by Local 401's lawyers.

"The Iron Workers Union condemns all acts of vandalism and does not condone such behavior. We need to remember that the indictment contains just allegations. All of the defendants are innocent until proven guilty," the statement continued.

Dougherty has retired from the union, his lawyer, Fortunato N. Perri Jr., said, adding, "Mr. Dougherty maintains his innocence."

Dougherty did not do any of the violent acts alleged in the indictment, Perri said, and tough conversations captured on the telephone are "more bluster than anything else."

Prosecutors allege that Dougherty and others cost contractors hundreds of thousands of dollars over at least three years, and were indiscriminate in choosing their targets - willing to swing baseball bats at a Toys R Us work site in King of Prussia or torch a Quaker meetinghouse under construction in Chestnut Hill.

The new charges include 14 additional allegations of extortion and "night work," listing incidents at elementary schools in Wallingford and Sharon Hill, a firehouse in Eddystone, and an assisted-living facility in Horsham.

Charged in the superseding indictment were Dougherty and union official Richard Ritchie; business agents Edward Sweeney, Francis Sean O'Donnell, Christopher Prophet, and William O'Donnell; and members James Walsh, William Gillen, Daniel Hennigar, and Greg Sullivan.