A federal watchdog is looking into whether United Auto Workers President Shawn Fain made demands to benefit his domestic partner and her sister, according to The Wall Street Journal.

The allegations came in a court filing by a lawyer for federal monitor Neil Barofsky. Barofsky is looking into whether union officials are complying with a 2020 settlement that came after a multiyear corruption investigation which resulted in several former union leaders being sent to prison.

According to the Journal, Barofsky is looking at Fain’s decision in May to remove UAW Vice President Rich Boyer from his role as the union’s top negotiator with Stellantis. The probe would determine if the move was in retaliation for Boyer’s alleged “refusal to accede to demands” to take actions that “would have benefitted (Fain’s) domestic partner and her sister.”

The monitor has been investigating Fain, secretary-treasurer Margaret Mock, and allegations of retaliation by Fain against Boyer. The monitor also began investigating a regional director after receiving allegations of potential embezzlement, according to the Associated Press.

The UAW has been involved in attempts to unionize the Mercedes-Benz auto plant in Tuscaloosa County, and the Hyundai plant in Montgomery. A vote on unionization at Mercedes in May failed, with some 56% of the nearly 4,700 workers who voted cast their ballots against unionizing.

The UAW subsequently filed with the National Labor Relations Board to reject the election and order a new election.

See also: Why the union vote failed at Alabama’s Mercedes-Benz plant