A federal ethics watchdog wants the White House to probe an alleged violation of ethics rules by the White House official in charge of ensuring compliance with those rules.

The Office of Government Ethics on Wednesday referred the allegations to White House Counsel Don McGahn, asking him to look into whether McGahn deputy Stefan Passantino violated conflict-of-interest provisions imposed by President Donald Trump in January.

Passantino is the White House’s designated agency ethics official, meaning he is in charge of ensuring White House staff compliance with rules imposed by the president and other ethics measures designed to prevent corruption and conflicts of interest.

It was in that capacity that a group of Democratic senators alleged he ran afoul of the same rules with which he has been charged with enforcing.

In an April letter to Passantino, the senators indicated that he may have violated conflict-of-interest rules by overseeing White House legal work that determined that billionaire investor Carl Icahn, a friend of Trump’s, was not subject ethics regulations due to his status as an informal adviser to the president.

“He is simply a private citizen whose opinion the president respects and whom the president speaks with from time to time," Passantino told Bloomberg Business in March. "Mr. Icahn does not have a position with the administration nor a policymaking role."

The lack of an official administration role for Icahn has allowed him to evade ethics requirements—including financial disclosure, recusal from policymaking that might affect his bottom line, or divestment from assets affected by that policymaking—required of formal presidential advisers.

As Icahn has played that informal advisory role, his investment portfolio has benefitted handsomely from Trump administration policies.

Passantino’s role in determining the applicability of ethics rules to Icahn may itself have violated ethics rules, the senators alleged in their April letter, due to his past legal work for Icahn.

Those rules bar federal appointees from participating in “particular matters involving specific parties” that employed or paid for the services of those appointees previous the last two years. According to Passantino’s financial disclosure filings, he provided legal services to an Icahn company last year.

“Mr. Passantino is subject to the former client restrictions with respect to Mr. Icahn,” OGE director Walter Shaub wrote to the senators on Thursday. “For that reason, it is concerning that your letter cites a news report that Mr. Passantino delivered the White House's legal position on Mr. Icahn's employment status to the media.”

But Shaub said OGE does not have sufficient information to determine whether a violation occurred, and referred the matter to McGahn. “By copy of this letter, I am bringing the matter to the attention of the Counsel to the President for his review and a determination as to whether action is warranted,” Shaub wrote.

The White House insisted that Passantino had not run afoul of any ethics rules, and accused those alleging a potential conflict of interest—including OGE—of waging a political fight against the administration.

“Mr. Passantino has not so much as spoken with Mr. Icahn since joining the administration and merely reiterating a fact [in his statement to Bloomberg] which was made by the transition team stating that Mr. Icahn doesn't work for the White House is neither a particular matter nor legal advice and no reasonable person would think otherwise,” White House spokesperson Kelly Love said in an email.

Both the Democratic senators who sent the initial letter and OGE director Shaub, Love said, “are once again distorting facts and attempting to tarnish the White House for purposes of a partisan agenda.”

The White House counsel’s office has previously clashed with OGE over the scope of rules imposed by the president’s January executive order. In other cases, the counsel’s office has concluded that potential violations referred by OGE did in fact run afoul of ethics rules, but has declined to impose any sanctions on the offending White House officials.

“The White House is in a position to ascertain the relevant facts and is responsible for monitoring its appointees' compliance with ethics requirements,” Shaub wrote in his Wednesday letter.

Passantino’s alleged violation, in other words, will be adjudicated by the same office that employs him.