IDAHO FALLS, Idaho (KTVB)-- The search for a missing 5-year-old believed to have been kidnapped from Idaho and taken to Mexico is now entering its fourth day. That's after the initial abduction was revealed on Facebook, according to the child's grandmother.

Authorities believe Aaliyah Alynn Esqueda, 5, was taken by her paternal grandparents on Wednesday from Idaho Falls. Aaliyah is cared for by her grandparents, Debra and Scott Yagues. The Yagues allow Aaliyah's father's parents, Irene and Salvador Esqueda visitation. Debra Yagues says little Aaliyah was supposed to be returned to her home by 5 p.m. Sunday. But that didn't happen.

Yagues tells KTVB she had been allowing Aaliyah's paternal grandparents visitation rights with the child on Wednesday when she received the shocking news. Yagues says she called her attorney and then Idaho Falls police, who eventually issued an Amber Alert. Authorities believe the three left Idaho Falls on Wednesday around 11:00 p.m. on a bus headed for Mexico.