Longtime confidant of President Trump and wealthy real estate investor Tom Barrack was interviewed by special counsel Robert Mueller's team, according to the Associated Press citing three people familiar with the matter.

Why it matters: Barrack "has rare access and insight into Trump going back decades," per the AP. The questions Mueller's team had for him were unclear, although the AP adds that people familiar said they focused primarily on Rick Gates and Paul Manafort, as well as "financial matters about the campaign, the transition and Trump's inauguration."