"Diddier Pacheco Salazar, 22, appeared before Judge Monica Herranz to plead guilty in a DUI case on January 27 in Multnomah County, Oregon.
Salazar entered the courtroom with his lawyer but never came back out again.
Herranz is now under internal investigation after U.S. Attorney Billy Williams accused the judge of letting Salazar leave through her private entrance after staff realized immigration and customs enforcement agents were waiting for him.
Every courtroom in the Multnomah County Circuit Court has three doors - one for the public, a private judge entrance and one for inmates to be brought in from jail.
Williams told KOIN the only explanation was that Herranz - who is on the board of the Oregon Hispanic Bar Association - or a member of her staff helped Salazar to leave through another door.
ICE agents brought the matter to Williams after the incident allowed Salazar to evade the immigration officials."