The 50-year-old teacher and his 15-year-old student had not been seen since March 13

The former Tennessee teacher accused of abducting his female student has been arrested, and the student has been safely recovered in Northern California, the Tennessee Bureau of Investigation announced Thursday.

On March 13, Tad Cummins, 50, vanished with Elizabeth Thomas, then his 15-year-old student at Culleoka Unit School in Maury County, Tennessee.

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The pair was the subject of an ongoing AMBER Alert, and investigators had said they were “off the grid.”

TBI spokesperson Josh Devine tells PEOPLE, “Someone in California saw them and called authorities. That’s the power of the public in a situation like this, in an AMBER Alert.”

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Devine says the pair was found in a cabin. The TBI announced it would reveal more details at a 4 p.m. ET press conference.

Thomas’ older sister, Kat Bozeman, tells PEOPLE, “We’re absolutely thrilled and blessed to have her safe and on her way home. It’s amazing. This is the best day we could have imagined.”

Bozeman says investigators told the family “she appeared to be in physically healthy condition. We don’t know about her mental state as of this moment.”

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Authorities allege Cummins “groomed” Thomas for months. Cummins was suspended from his job after he was allegedly caught kissing Thomas on school grounds, and he was fired after he and Thomas went missing. The two allegedly exchanged emails officials described as “romantic” in nature.

A warrant had been issued for Cummins’ arrest on charges of aggravated kidnapping and sexual contact with a minor — the latter charge stemming from the alleged January kiss.

Alleged ‘Grooming’

Thomas’ father, Anthony Thomas, told PEOPLE that Cummins “built up a system where she was dependent on him.”

He says Cummins helped Elizabeth with homework and “[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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Image zoom Courtesy TBI

Cummins worked for more than a decade in the medical field, where Elizabeth aspired to work, before he became a teacher.

“It just so happened that she wanted to do the things he was claiming [he did], so she probably idolized [him],” Elizabeth’s sister Sarah Thomas told PEOPLE.

“He took that interest to kind of manipulate, to gain control over her, to gain her favor,” Sarah said.

RELATED VIDEO: Tennessee 15-Year-Old and Her Teacher, 50, Spotted in Oklahoma Days After He Allegedly Kidnapped Her

Wife Filed for Divorce

During the period they were missing, Cummins’ wife, Jill Cummins, filed for divorce after 31 years of marriage.

“Jill will attempt to move forward with her life. This is a difficult time for her and her family,” her attorney wrote in a statement obtained by PEOPLE.

Image zoom Courtesy Cummins Family

In an interview with ABC News, she said, “Of course I love him. I forgive him and I still love him…. But it doesn’t mean I could ever trust him again. Because he betrayed my trust to a point that that’s totally broken.”

Jill said she thought her husband was simply mentoring Thomas, noting that she and Cummins even took Thomas, along with a group of children, to church.

TBI Director Mark Gwyn said in a statement: “Our intelligence analysts and agents have worked tirelessly since issuing this AMBER Alert to process more than 1,500 leads from all 50 states. What happened in California this morning, however, proves it only takes one person to lead to a successful end.”