John Yu talked to CNN's Ashleigh Banfield saying there was a lot of drama leading up to his sister's disappearance.
John Yu, the brother of 16-year-old Amy Yu says a month before his sister and 45-year-old Kevin Esterly went on the run, there was a dramatic confrontation at the Yu Household involving Esterly and his wife.
"They were blasting, yelling about they think that Amy and Kevin Esterly are sleeping together and doing some stupid stuff," Yu said.
Yu says he believes his sister went willingly and that she and Esterly planned their disappearance.
"I think they know or they planned it, to do this and I think it was both of their ideas because Amy is not that stupid," Yu said.
The March 5th disappearance of Amy Yu and Esterly has created a media frenzy and made it a constant source of discussion on social media.
Many people are worried about Yu's safety.
Samuel Chen is Yu's former youth pastor and says before Yu left she sent a few Snapchats to friends saying, 'I'm done with this place, I'm done with people who don't like me.'"
But Chen says people do like her and he believes she will want to come home sooner rather than later.
"But at the end of the day, he is not going to be enough, she's going to need her friends, she's going to need that social media interaction, she's going to need her family and she's going to realize it, and I think sooner than later," he said.
The Allentown Police Department believes Yu and Esterly are watching media reports so information is limited.
69 News does know that local, state and federal investigators are on the case. Yu's family says they just want her to come home safely.
Allentown, PA 18102