Federal authorities are now involved in the Timothy Busfield child sex abuse case … TMZ has learned.

A spokesperson for the Albuquerque Police Department tells TMZ … the U.S. Marshals Service is assisting APD as officers work to locate Busfield and take him into custody in connection with the allegations.

As we previously reported … Melissa Gilbert‘s husband was accused of sexually abusing underage boys who were child actors on “The Cleaning Lady” while he was directing the show. An investigation into Busfield began in November 2024, and a warrant for his arrest was issued Friday.

We’re told Busfield is not currently in custody, and law enforcement has not provided a timeline for an arrest. His whereabouts have not been publicly disclosed.

During a police interview, Busfield told detectives the show’s lead actress, Élodie Yung, claimed the mother of the two boys wanted revenge after her children were not invited back for the show’s final season.