Donald Trump’s former lawyer secretly taped a conversation the pair had about payments to an ex-Playboy model, according to a report.
Michael Cohen reportedly recorded the discussion before the presidential election in 2016, which Mr Trump went on to win.
According to the New York Times, the FBI seized the recording this year during a raid on Mr Cohen’s office.
Karen McDougal is a former Playboy model who says she had an affair with Mr Trump for nearly a year in 2006, shortly after Melania Trump gave birth to son Barron.
She sold her story to The National Enquirer in the final months of the presidential campaign but the tabloid did not publish it, keeping it from becoming public.
In March, she sued the publication, asking to be released from their agreement forbidding her from talking about the alleged affair.