From interviews with family, friends, police, attorneys in the case, as well as court affidavits, here's what we know:
-- 2009 to 2010: Yu and her mother, Miu Luu, meet Esterly, a construction contractor, at a church in Lowhill Township, Pennsylvania. Amy is about 7 or 8 years old.
-- November 2017: Yu signs documents at Lehigh Valley Academy Charter School in Hanover Township, Pennsylvania, describing Esterly as her stepfather, which allows him to check her out of school.
-- Feb. 9, 2018: Yu's mother goes to pick up her daughter at Lehigh Valley Academy Charter and learns that Esterly had already picked her up and that Yu had listed him on school documents as her stepfather. The mother also discovers that Esterly had signed out her daughter from school at least 10 times. Luu confronts Esterly that same day over why he had been secretly picking up her daughter at school.
-- Feb. 15: Allentown police investigators visit Esterly and his wife, Stacey, at their Allentown home and advises them both to stay away from Yu and that the girl's mother didn't want them to have any further contact with her.
-- March 5: Luu drops Yu off at her bus stop, but the teenager doesn't take it to school. On the same day, Esterly withdrew $4,000 from his wife's bank account. Luu reports her daughter missing to the Allentown Police Department.
-- March 7: Allentown police issue a missing person alert for Yu and obtain a warrant for Esterly's arrest.
-- March 8: Police discover that Yu and Esterly boarded a one-way flight from Philadelphia to Cancun, Mexico, which briefly stopped in Dallas.
-- March 10: Luu speaks to ABC News, saying, she was "waiting and waiting and praying, and I don't know if they can catch him [Esterly] or not." She also says Esterly's daughter "is a friend and just one year younger than Amy. I never thought he would act like that."
-- Thursday: Authorities in Mexico issue an Amber Alert for Yu.
-- Friday: Esterly's wife, Stacey, issues a statement through her attorney, saying she and her husband fought over his relationship with Yu and she pleaded with the teenager to come home.
-- Saturday: Authorities in Mexico find Yu and Esterly at a Puerto Moreles resort near Cancun and arrest Esterly on suspicion of child custody interference. Both Esterly and Yu are flown back to Miami, where he was awaiting extradition to Pennsylvania.
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