WASHINGTON — Donald Trump tapped a man to be a senior business adviser to his real-estate empire even after the man’s past involvement in a major Mafia-linked stock fraud scheme had become publicly known, according to Associated Press interviews and a review of court records.

Portions of Trump’s relationship with Felix Sater, a convicted felon and government informant, have been previously known. Trump worked with the company where Sater was an executive, Bayrock Group LLC, after it rented office space from the Trump Organization as early as 2003. Sater’s criminal history was effectively unknown to the public at the time, because a judge kept the relevant court records secret and Sater altered his name. When Sater’s criminal past and Mafia links came to light in 2007, Trump distanced himself from Sater.

But less than three years later, Trump renewed his ties with Sater. Sater presented business cards describing himself as a senior adviser to Donald Trump, and he had an office on the same floor as Trump’s own office in New York’s Trump Tower, The Associated Press learned through interviews and court records.

Trump said during an AP interview on Wednesday that he recalled only bare details of Sater.

“Felix Sater, boy, I have to even think about it,” Trump said, referring questions about Sater to his staff. “I’m not that familiar with him.”