WASHINGTON (AP) — A key figure in the federal investigation of Republican Rep. Matt Gaetz is expected to plead guilty to criminal charges next week. Court documents show Joel Greenberg will appear Monday in federal court in Orlando, Florida, for a change of plea hearing. He has been working for weeks toward a deal with federal prosecutors who are investigating sex trafficking and public corruption allegations. The plea potentially escalates the legal and political jeopardy the Florida congressman is facing. Federal prosecutors are examining whether Gaetz and Greenberg paid underage girls or offered them gifts in exchange for sex, according to people familiar with the matter. Gaetz has vehemently denied the allegations and insists he will not resign his seat in Congress.