The father of missing teen Mary Catherine Elizabeth Thomas thinks his daughter was prayed upon by her former teacher and alleged abductor, Tad Cummins

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The father of missing 15-year-old Mary Catherine Elizabeth Thomas thinks his daughter was preyed upon by her former teacher and alleged abductor, Tad Cummins, while she was at school.

Thomas, who goes by Elizabeth, was reported missing in Maury County, Tennessee, on the afternoon of March 13 — after she asked a friend to drop her off at a local Shoney’s that morning.

The Tennessee Bureau of Investigation suspects she is now with Cummins, 50, who has been charged with aggravated kidnapping and sexual contact with a minor. The latter claim stems from an alleged kiss between him and Thomas in January, on school property, that eventually led to Cummins’ firing, according to the TBI.

“He built up a system where she was dependent on him,” Thomas’ dad, Anthony, says of Cummins’ alleged efforts to woo the high school freshman.

In addition to homework help, Anthony says Cummins “[gave] her money, bought a microwave so she would heat food up in his room [and] try and get her out of trouble.”

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From left: Mary Catherine Elizabeth Thomas and Tad Cummins.
| Credit: TBI

Speaking to PEOPLE for the first time since his daughter’s disappearance, Anthony says he had no idea there might be something going on between Elizabeth and Cummins. Then Cummins was allegedly caught kissing her in his classroom at the Culleoka Unit School on Jan. 23.

When Anthony confronted his daughter, he says she denied it. Worried, he told her not to contact Cummins again.

“She had always had a lot of confidence about herself, and suddenly this year she had been very outwardly saying that she thought she was ugly,” Anthony says.

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“It must have been Tad was the only one who was making her feel good,” her father adds. “I told her several times she was beautiful.”

But he worries Elizabeth has “totally been absorbed by [Cummins’] delusions.”

Still, he hopes a message will reach his daughter: “Please come home. Get away from that man and come home. Everybody here loves you. That man is just using you.”

From left: Tad Cummins and Elizabeth Thomas days before their alleged kiss.
| Credit: Courtesy TBI

With the investigation in its second week, Anthony says he remains hopeful and will welcome his daughter back with open arms: “It will be a day we’ll be rejoicing.”

He says he’s prepared to help Elizabeth understand how she was victimized, even if she does not see it at first. “She’s going to have a lot of work to do,” he says.

Authorities allege Cummins is likely keeping Elizabeth “off the grid,” and they urge the public to search their properties, local campgrounds, rural areas and parking garages.

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The TBI asks anyone who believes they spot Cummins or Elizabeth to not approach them and instead keep an eye on them while calling 911.

The teen was last seen wearing a flannel shirt and black leggings. She is 5 feet 5 inches tall and weighs 120 lbs., with blonde hair and hazel eyes.

Cummins was seen driving a Silver Nissan Rogue with Tennessee license plate 976ZPT, according to the TBI. He is 6 feet tall and weighs 200 lbs., with brown hair and eyes.

Anyone with information on Cummins or Elizabeth should call the TBI at 1-800-TBI-FIND.