A 16-year-old Allentown girl who went to Mexico with a 45-year-old man is home, and the man is in custody, federal authorities said Sunday.

Amy Yu and Kevin Esterly have been missing since March 5. Yu's mother, Miu Luu, reported her missing that day when the teen did not return home from Lehigh Valley Academy Charter School in Hanover Township, Northampton County.

The mother told the Allentown Morning Call that she cried when she heard her daughter had been found.

"For two weeks, I've had trouble sleeping and eating," Luu told the newspaper. "I'm very happy."

Yu and Esterly were taken into custody Saturday morning in Playa del Carmen, in Quintana Roo state, according to Immigration and Customs officials. The Associated Press reported that the two were flown to Miami, where Esterly remained for processing while Yu went on to Philadelphia. She arrived Sunday and returned to Allentown. Esterly will be charged with child custody interference when he arrives in Pennsylvania.

Their apprehension was the result of a joint effort by ICE, Homeland Security Investigations, the U.S. Marshals Service and the Policia Federal Transnational Criminal Investigative Unit.

The case has made headlines in the Lehigh Valley and beyond. Allentown police held a news conference Friday to say the teen willingly went with Esterly, a father of two. They bought one-way tickets from Philadelphia to Dallas and then headed to Cancun, police said.

Investigators said the two apparently had a secret relationship for months. Police said Yu had listed Esterly as her stepfather on her school records so he could check her out of school, according to the Associated Press. Esterly had signed her out of school 10 times in the last few months, police said.

Mexican authorities issued an Amber Alert Thursday saying that Yu was believed to be traveling with Esterly and that she "may be a victim of a crime."

On Friday, Esterly's wife, Stacey, gave a statement to the Allentown Morning Call, pleading for the teen and her husband to return home from Mexico.

Kevin Esterly and his family have known Yu for about eight years, having met through church, according to the Morning Call. The paper quoted Stacey Esterly's attorney as saying the husband and wife had been fighting since the summer about his relationship with Yu.

The attorney, John Waldron, told the Morning Call that Stacey Esterly was "very happy and relieved" that her husband and Yu had been found.

"She wants Amy home with her mom, that is what she has always wanted," Waldron said. "She is glad that Amy is safe and that Kevin is with authorities."