The sentence carries a mandatory minimum of 15 years in prison.
Dougherty, 73, was accused of using arson, intimidation and violence against non-union contractors, in an effort to secure jobs for his Local 401 union, NBC reports.
A dozen other union members were indicted last February — 11 pleaded guilty and a handful testified against Dougherty during his trial. Prosecutors said Dougherty took advantage of ironworkers, NewsWorks reports.
"Ironworkers who joined goon squads got the best jobs and promotions," said Livermore in his opening statement on Jan. 5. "Union members faced a stark choice: Join the goon squad or get in the back of the line for a job."
According to Philly.com, U.S. District Judge Michael M. Baylson set a sentencing date of April 29.
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