The Justice Department is reportedly looking into ​allegations that United Auto Workers President Shawn Fain took improper action to try to help his fiancée and retaliated against another ‌senior union member who objected to the efforts.

Reuters is reporting the purported probe based on what the newswire service says is a review of internal union documents.

The lead counsel for the federal watchdog appointed to oversee union activities last month told Fain and the senior union member, Rich Boyer, that the DOJ had begun a grand jury investigation into matters detailed in the monitor's reports including ​those involving Fain and his fiancée.

Fain has denied the monitor's finding and said Sunday, as news broke about the probe, "We are going to fight back hard." 

Fain is ⁠campaigning for a second four-year term as the leader of the union, and Boyer is among several challengers. The election is scheduled for later this year.

The monitor issued a report in July that concluded Fain had retaliated against Boyer and improperly used his authority, ​including in ways that would benefit his fiancée. However, the monitor deferred a decision on disciplinary action pending further review without citing the federal probe, Reuters also reports. 

Bloomberg has also reported that the DOJ is probing allegations related to Fain. 

The UAW declined to comment. ‌A lawyer ⁠representing the union said it is not the subject of a grand jury investigation. Boyer and his attorney didn't immediately respond to requests for comment.

The DOJ also did not respond to Reuter's request for comment before the wire service posted its story Sunday.

Fain has also said the monitor has a "political grudge against me because the UAW took an anti-war stance about what was happening in Gaza."