Representative Matt Gaetz, Republican of Florida, was one of President Donald J. Trump’s most vocal allies during his term, publicly pledging loyalty and even signing a letter nominating the president for the Nobel Peace Prize. In the final weeks of Mr. Trump’s term, Mr. Gaetz sought something in return. He privately asked the White House for blanket pre-emptive pardons for himself and unidentified congressional allies for any crimes they may have committed, according to two people told of the discussions. Gaetz’s push for a pardon, first reported by The New York Times, came during the closing months of the Trump-era Justice Department when federal investigators were beginning an investigation into whether the Florida congressman had a sexual relationship with a 17-year-old girl.

It was unclear whether Mr. Gaetz or the White House knew at the time about the inquiry, or who else he sought pardons for. Mr. Gaetz did not tell White House aides that he was under investigation for potential sex trafficking violations when he made the request. But top White House lawyers and officials viewed the request for a pre-emptive pardon as a nonstarter that would set a bad precedent, the people said. A person briefed on the probe confirmed to CNN that federal authorities were investigating Gaetz as part of a broader probe into trafficking allegations against another Florida politician, an investigation that began in the closing months of the Trump-era Justice Department under Attorney General William Barr. Gaetz has not been charged with any crimes and the investigation is still in its early stages, according to sources familiar with the matter.