(CNN) -- A former Tennessee teacher has been added to the state's "Top 10 Most Wanted" list after being charged with aggravated kidnapping in the disappearance of a 15-year-old girl.
Authorities say Tad Cummins, 50, kidnapped Elizabeth Thomas, a freshman at the high school where Cummins taught until this week. The girl is in imminent danger, they said.
Cummins also has been charged with sexual misconduct with minor.
The teacher's wife delivered an emotional appeal Friday for her husband to turn himself in.
"Tad, this is not you. This is not who you are," Jill Cummins pleaded during a news conference." Please do the right thing and turn yourself in to the police and bring Beth home."
With tears in her eyes and standing beside her pastor, Cummins spoke directly to her husband via the TV cameras: "We can help you get through this. No matter how far you've gone or what is happening right now, God's grace is sufficient for you and he wants you to come home."
Jill Cummins' entreaty to her husband came four days after an Amber Alert was issued for Elizabeth Thomas.
A friend dropped off the teen Monday at a restaurant in Columbia, Tennessee, near the high school, law enforcement authorities said; the restaurant is about 45 miles south of Nashville. Around the same time, Cummins was recorded by a surveillance camera getting gas at a nearby service station, authorities said.
Later that afternoon, Thomas and Cummins were about 80 miles away in Decatur, Alabama, Tennessee Bureau of Investigation officials said they suspect. Neither has any known connection there.
Investigators believe Cummins is now hiding out in secluded areas or has left the Southeast with the girl. Police are trying to evaluate how much cash he may have. Cummins took out a $4,500 loan a few days before he disappeared, police say.
The TBI on Friday tweeted pictures of Cummins captured during the past few weeks.
Cummins, who taught in Culleoka, Tennessee, was fired earlier this week, the TBI said. His dismissal came after authorities issued a warrant for him on the sexual misconduct charge.
That charge was based on an "alleged interaction" with a teen, the TBI said. Cummins was not Thomas' teacher, and the history of their relationship is unknown, TBI Private Investigative Officer Josh Devine said.
Cummins at some point had been suspended from his teaching job for more than a month for inappropriate contact with a student and sexual contact with a minor, Maury County Sheriff Bucky Rowland. The sheriff did not specify when the suspension happened.
Cummins may be driving a 2015 Nissan Rouge with Tennessee license plate 976 ZPT and is believed to be armed with two handguns, the TBI said. A reward has been offered for any information that may lead to an arrest.
Tips are coming in, but no one has reported seeing the vehicle or Cummins and Thomas, officials said.
"This is a 15-year-old child that has led a difficult life, basically going against a 50-year-old man. I believe it's clear at this point that her removal by him is unlawful. And what makes it aggravated is that he was in possession of firearms," said District Attorney Brent Cooper, who has jurisdiction in this case.