The FBI on Wednesday morning raided a Michigan home belonging to United Auto Workers (UAW) President Gary Jones along with a conference center often used by union leaders.

A neighbor of Jones said he noticed federal agents removing "a bunch of boxes" from the house at around 8:30 a.m. with the authorities also "going through a bunch of cash in the garage."

The raids are the latest developments in a multiyear federal corruption investigation into the upper hierarchy of the UAW, with the probe coming as the union attempts to negotiate new contracts for 158,000 workers.

Federal authorities are investigating allegations of bribes and kickback among union leadership, with Fiat Chrysler executives and UAW leaders being targeted for misusing funds for an employee training center.

Jones is the highest ranking-UAW official being investigated by the FBI. He had previously stated in March that he has wanted the union to become more financially transparent, as the federal investigation first became public in 2017.

So far, nine people have been charged as part of the investigation, including Norwood Jewel, a former UAW vice president who was charged with allegedly receiving tens of thousands of dollars in illegal payments from Fiat Chrysler automobiles in March.

The investigation has also expanded to include auto giant General Motors, with senior retired union official Michael Grimes, who worked for the union's GM division, charged with wire fraud and conspiracy to commit money laundering for receiving $2 million in kickbacks from GM vendors while serving on a joint GM-UAW nonprofit. GM called the allegations a "stunning abuse of power and trust."