More News:

March 13, 2018

Mother to missing Allentown teen: 'I just hope you come back'

Homeland Security reportedly joined the search for Amy Yu and the 45-year-old man she vanished with on March 5

Investigations Missing People
Yu Esterly Allentown Source/Allentown Police Department

Amy Yu, 16, and Kevin Esterly, 45, disappeared on Monday, March 5.

The mother of the Allentown teenager believed to have run off with a 45-year-old married man pleaded for her daughter's safe return in an interview on national television this week.

Mui Luu's daughter, 16-year-old Amy Yu, vanished on March 5 with 45-year-old Kevin Esterly, the father of one of Yu's friends.

In a "CBS This Morning" report on Monday, Luu told the network that the two families met through church and had befriended each other. Esterly had been to Luu's house for meals, and Yu often joined Esterly's family on their vacations, according to the report.

But shortly after the pair disappeared, police said Esterly and Yu had a "secretive relationship." Yu was last seen by her family at her bus stop in Allentown.

Authorities reportedly said on Monday that Yu had listed Esterly as her stepfather on school records, allowing Esterly to sign her out from the school she attended – Lehigh Valley Academy Charter School in Hanover Township, Northampton County – several times between November and February.

Esterly was barred from school grounds after Luu found out on Feb. 9 that he had signed Yu out of school without her mother's permission. Luu also told CBS News that she found text messages that suggested the two were romantically involved.

"I want to tell her, 'Amy, can you come back to me? I love you. I just hope you come back,'" Luu told the network. 

Allentown police first asked the public to help share news of the case in a Facebook post on Thursday.

Yu is 16 – the age of consent in Pennsylvania – and doesn't appear to have been taken against her will, but authorities have charged Esterly with interference with the custody of children. There is a warrant out for his arrest.

The Department of Homeland Security has also gotten involved in the case, which has garnered national and global media attention in recent days.

Allentown Police Chief Glen Dorney told the Allentown Morning Call on Monday they are still investigating the case, and that authorities believe Yu and Esterly are together and aware that police are looking for them.

Due to "national media interest," the police department told the newspaper that it would not release additional information as to "not hinder our investigative efforts."

Yu is described as an Asian female, 4 ft. 11 in. tall and weighing approximately 90 pounds. Esterly is described as a 5-foot-9, 185-pound white male. Police said last week that the pair may be traveling together in a 1999 red Honda Accord with the Pennsylvania plate number "KLT 0529."

Anyone who sees the pair or has information on their whereabouts is asked to contact Allentown Police at (610) 437-7751.