The FBI has set up a mobile command unit in Rexburg, Idaho, as the mother of two missing children is due to face charges there in connection to her children’s disappearance.

Tylee Ryan, 17, and Joshua “JJ” Vallow have not been seen since September, shortly after the family moved there from Arizona after Lori Vallow’s husband Charles Vallow was fatally shot this summer. Vallow, who married Chad Daybell in the fall, was arrested in Hawaii in late February after months of refusing to cooperate with the police investigation into her children’s disappearance. She was extradited to Idaho and is expected to arrive in Madison County any day now, where she will remain jailed on a $5 million bond.

East Idaho News reports that an FBI mobile command unit arrived in Rexburg on Monday, and is stationed next to the police headquarters.

“We continue to assist Rexburg Police and our command center is there to provide logistical support,” FBI spokeswoman Sandra Barker tells EastIdahoNews.com.

Vallow’s husband reportedly left Hawaii this weekend to return to Idaho. The couple fled Rexburg shortly after police discovered the children were missing during a welfare check in late November. Vallow had never reported the children missing, and allegedly lied to police about their whereabouts.

Daybell has not been charged in connection to his stepchildren’s disappearance.