By Eric Levenson CNN

(CNN) -- The Tennessee teacher and 15-year-old girl who are the subject of a manhunt were spotted at a Walmart in Oklahoma City earlier this month, the first confirmed sighting of the two since officials say the teacher kidnapped the girl.

Tad Cummins, 50, is suspected of abducting Elizabeth Thomas, his former student in Maury County, according to the Tennessee Bureau of Investigation (TBI).

"My precious little girl is out there, and we have to bring her home," Anthony Thomas, the teen's father, told CNN.

Elizabeth has been missing since March 13, not long after a student reported she saw the pair kissing, police say.

Surveillance images released Friday show Cummins and Elizabeth at a Walmart on East I-240 Service Road in Oklahoma City on the afternoon of March 15.

There, Cummins used cash to purchase various food items, according to the TBI. The images show that Cummins has darkened his hair and that Elizabeth may have red hair now. Investigators are working to determine what vehicle they were using.

Previous images showed Cummins had brown hair and a gray beard.

Thomas says that seeing photos after nearly three weeks without information about Elizabeth's whereabouts brought him "mixed emotions."

"It was good to be able to see her face, finally," Thomas said.

According to investigators, Cummins has brown eyes and is 6 feet tall and weighs about 200 pounds. Elizabeth has hazel eyes and is 5 feet 5 inches and weighs about 120 pounds. Officials believe Cummins is armed with two handguns and is driving a silver Nissan Rogue with Tennessee plates.

Cummins is charged with aggravated kidnapping and sexual misconduct with a minor, and he has been added to the state's "Top 10 Most Wanted" list, the TBI said.

Elizabeth was last seen when a friend dropped her off at a restaurant in Columbia, about 40 miles southwest of Nashville. Police believe Cummins picked her up from there and absconded.

At the time, Cummins was under investigation for inappropriate kissing with Elizabeth, his former student. The TBI said prior to leaving, she had done "online research on the topic of teen marriage."

CNN's Jason Hanna, Elliott C. McLaughlin, Madison Park, Faith Robinson, Natisha Lance and Nicole Chavez contributed to this report.

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