Federal agents on Wednesday raided the home of the president of the United Automobile Workers union in the midst of a widening investigation of financial wrongdoing by union and management officials.

Agents also executed search warrants at a 1,000-acre U.A.W. resort in Michigan and other locations, an F.B.I. spokeswoman said.

The investigation has uncovered the improper use of millions of dollars of funds — some of it earmarked for training union members — and bribery of union officials by auto executives. In some cases, the funds were spent on personal travel and purchases of Rolex watches and other high-priced items.

Eight people, including three former Fiat Chrysler executives, have been sentenced in the case. Another defendant, Michael Grimes, a former senior U.A.W. official, faces federal conspiracy charges.