The search for a missing 6-year-old Utah boy believed to have been taken by his biological mother has been upgraded to an Amber Alert.

On Sunday, the Unified Police Department asked for the public’s help to locate Terran Butler, who went missing along with his biological mother, Emily Jolley, following a court-supervised visit. On Monday, an Amber Alert was issued.

Butler was visiting Jolley on Saturday. When his father attempted to pick him up, it was discovered that Jolley had taken the boy from the residence without permission.

They were last seen together in the Millcreek area.

The boy is described as white with brown hair, last seen wearing a blue shirt, black gym shorts and blue hiking boots. Jolley is a 43-year-old white woman, described as being 5-foot-8 and 140 pounds, with brown hair and blue eyes.

Jolley has ties to Washington state, and is thought to perhaps be traveling there with Butler. She drives a blue 2008 Toyota Prius, with Utah license plate E847GT.

Anyone with knowledge about their whereabouts or the case is asked to contact UPD at 385-468-9686.