In his annual disclosure of personal finances, President Trump acknowledged that he paid lawyer Michael Cohen between $100,000 and $250,000 last year.
Cohen and Trump defense attorney Rudolph Giuliani have both said some of that money was to reimburse Cohen for a $130,000 hush money settlement with adult film actress Stormy Daniels, who says she had an affair with Trump.
Trump's revelation came in his signed disclosure report, required by federal ethics law. The Office of Government Ethics flagged the disclosure in a letter to Deputy Attorney General Rod Rosenstein, who oversees the investigation led by special counsel Robert Mueller into whether the Trump campaign colluded with Russia in 2016.
The money owed to Cohen wasn't listed on Trump's 2017 report, although the disclosure should include current liabilities of $10,000 or more. Giuliani has discussed the debt in TV appearances and told The Washington Post Trump owed Cohen $250,000.
The watchdog group Citizens for Responsibility and Ethics in Washington asked the Justice Department and OGE earlier this month to investigate the omission of the Cohen liability from the 2017 report.
A related question is whether the payment to Daniels, coming just a few days before the 2016 election, was related to Trump's run for the White House. That would make it a campaign expense — an illegal one because it wasn't made with campaign contributions or disclosed on campaign financial reports.
This story has been updated.