United and Georgetown officials said they did not want to comment.
Had Murrell not signed, United would have retained his MLS rights through 2025.
Troy Lesesne, a coach on the rise, is set to lead D.C. United
Murrell is a McDonogh School graduate from Forest Hill, Md., who came through Pipeline SC, a Baltimore area youth program co-founded by former United attacker Santino Quaranta.
He posted seven goals and four assists his freshman year at Georgetown and 11 and four respectively this past season, including eight goals in the first nine matches. Last summer, Murrell played for the Annapolis Blues in the National Premier Soccer League, a fourth-division amateur circuit.