The House Ethics Committee directed GOP Rep. Madison Cawthorn of North Carolina to pay nearly $15,000 to a charity Tuesday after finding “substantial evidence” that he improperly promoted a cryptocurrency while in Congress.

The fine caps an investigation announced in May that looked into whether the scandal-plagued lawmaker touted a cryptocurrency known as a Let’s Go Brandon coin in which he had a financial interest, and whether he engaged in “an improper relationship” with an aide on his congressional staff. The committee said in its 81-page report that it did not find evidence of improprieties between Cawthorn and the staffer.

However, the subcommittee that conducted the probe said Cawthorn violated rules against conflicts of interest surrounding the cryptocurrency and directed him to pay $14,237.49 to an appropriate charitable organization by Dec. 31.

It also found that Cawthorn, 27, failed to file timely reports to the House “disclosing his transactions relating to the cryptocurrency.” And even though the panel determined that he did not knowingly fail to file the disclosures in a timely fashion, he was still required by law to pay $1,000 to the Treasury Department in late fees.

NBC News has reached out to Cawthorn’s office for comment.

The House probe came after an April complaint filed with the Office of Congressional Ethics by the American Muckrakers PAC citing a Washington Examiner article that named “multiple watchdog groups” suggesting the first-term lawmaker may have violated insider trading laws in an alleged cryptocurrency scheme.

In its complaint, the PAC also accused Cawthorn of having a relationship with one of his aides.

The subcommittee which reviewed documents and interviewed Cawthorn and six other witnesses in connection with the allegations, said it did not find evidence that Cawthorn engaged in an improper relationship with a member of his staff “and recommended no further action with respect to that allegation.”

Cawthorn, who was backed by former President Donald Trump in this year’s GOP primary, lost his renomination bid shortly after causing an uproar when he claimed on a podcast that aired in March that unnamed, older congressional colleagues were using drugs and that some of them had invited him to a “sexual get-together.”

This article was originally published on NBCNews.com