Sophia was in the custody of the Arizona department of Child Protective Services at the time of her abduction, and lived in Tempe, Arizona. She had been placed into their care when she was two days old because her older sister, Desiree Larranaga, died of shaken baby syndrome in 1995. No one has been charged in connection with Desiree's death and both of her parents maintain that they did not abuse the child.

Sophia's mother, Karla Carina Larranaga, abducted her on February 11, 1998, during a court-ordered visitation. A photograph and vital statistics for Karla are posted below this case summary. A felony warrant for kidnapping was issued for her on March 3, 1998. Karla and Sophia are thought to be in the Sinaloa, Mexico area. Her case remains unsolved.