A raid by the FBI and IRS was conducted Wednesday at the Canton Township, Michigan, home of United Automobile Workers (UAW) president Gary Jones, federal authorities confirm.

According to the Detroit News, the raids are part of an ongoing corruption investigation into auto industry efforts to influence union negotiations.

Eight people have pleaded guilty in an investigation of union officials and Fiat Chrysler executives enriching themselves with money from a job training center in Detroit. The probe appeared to widen two weeks ago when a former UAW official was charged with accepting kickbacks from union vendors.

“The UAW and President Gary Jones have always fully cooperated with the government investigators in this matter,” the UAW said in a statement. “As the leader of the UAW, President Jones is determined to uncover and address any and all wrongdoing, wherever it might lead. There was absolutely no need for search warrants to be used by the government today — the UAW has voluntarily responded to every request the government has made throughout the course of its investigation, produced literally hundreds of thousands of documents and other materials to the government, and most importantly, when wrongdoing has been discovered, we have taken strong action to address it.”

“Trust in UAW leadership is never more important than during the bargaining process, when profit-laden auto companies stand to benefit from media leaks, false assumptions, and political grandstanding,” the statement adds. “The sole focus of President Jones and his team will be winning at the bargaining table for our members.”

For two years, the union has dealt with unflattering stories about senior leaders turning the UAW-Fiat Chrysler center into a personal piggy bank. The government said General Holiefield, who was responsible for negotiating with Fiat Chrysler on behalf of the union, had a $262,000 mortgage paid off in 2014. He died in 2015.

Norwood Jewell, who moved into Holiefield’s job, was recently sentenced to 15 months in prison. His plea deal listed $60,000 in meals and golf paid with training center credit cards.

The Associated Press contributed to this report.