Investigators say Amy Yu, 16, and Kevin Esterly, 45, took off on March 5, leaving the Allentown area for Mexico where they were discovered this weekend.
"I hope he's in jail forever!" Amy's mother, Miu Luu says Esterly was obsessed with her daughter.
"Kevin with her, is a long time together before Amy was 16 years old. Amy's 8-years-old and goes to his house a lot of times. I have pictures of them, the families together. I can't believe Kevin would do that," said Luu.
Amy and Esterly first met through church nearly a decade ago, according to family members.
Investigators say Amy was friendly with Esterly's oldest daughter.
He has four children, all daughters.
In recent years, Amy's mother says things became inappropriate.
Esterly reportedly rented an apartment near Amy's Allentown home and on 10 occasions, signed her out of her charter school in Bethlehem, pretending to be her step-father.
"That day, the police talked to Kevin. They said, 'You have no more contact.' So he's angry because I called the police," said Luu.
Amy's mother showed Newswatch 16 text messages on her phone, which she says were from Kevin before he and Amy ran away.
One read, in part: "She is just a kid and the funny thing is at one point in her life, you were doing the right thing, you gave up when it got a little tough and I started to fix that kid and you guys made me stop for no reason."
An attorney for the Esterly family says Esterly's wife learned of the relationship and was furious. She was ready to go to police when she says Esterly took off with Amy.
The story grabbed national attention.
"I have a 12-year-old daughter. I couldn't fathom. I'm 46. It just doesn't make sense. There's something wrong with him," said Thomas Canon of Allentown.
"I have a daughter of my own, and it just, it's scary. You don't know who to trust. It's sad. I'm glad she's home and safe," said Saul Vachier of Allentown.
Esterly is being held in Florida and told a judge he wants to return to Pennsylvania.
As for Amy, her mother says Kevin Esterly poisoned her mind, and Amy does not want to return home, so she was briefly hospitalized and is now in a place that can help her with mental health care and other interventions.
"She doesn't want to go in the house. She doesn't want to see me. I go to the hospital. The nurse says she doesn't want to see anybody," said Luu.
There is no word when Esterly will be brought back to the Allentown area.
The Esterly family attorney said Esterly's wife is in the process of filing for divorce.