On Thursday, after over a month of searching by police, they were found in a cabin in a remote area of northern California and Cummins was subsequently arrested.
TBI spokesperson Josh DeVine said Thomas and her former high school teacher were found in a cabin in a remote area with little or no cell service.
Elizabeth Thomas was allegedly abducted from Culleoka, Tennessee by her 50-year-old teacher Tad Cummins on March 13.
After the capture, one federal charge of transportation of a minor across state lines for the goal of having criminal sexual intercourse was filed against Cummins, said Jack Smith, acting USA attorney for the Middle District of Tennessee.
Tennessee Bureau of Investigation director Mark Gwyn thanked people across the country for their assistance with finding Elizabeth. The agency said it planned a news conference for 4 p.m. EDT to release more details.
"Because we love her so much, we're gonna be patient with her", he said.
April 12, 2017: District Attorney Brent Cooper said Cummins left a note for his wife, Jill, on the morning of March 13, the day he and Thomas vanished. She and Cummins have been missing more than two weeks now.
Cummins faces state charges of aggravated kidnapping and sexual contact with a minor as well as a federal charge of taking a minor across state lines to have sex.
"The news of Elizabeth Thomas' safe return is wonderful news for our community, and now, we can begin healing as a community", Maury County Public Schools said in a statement.
The Siskiyou County Sheriff's Office then discovered Cummins' vehicle and put it under surveillance.More news: Westbrook sets triple-double record, Thunder beat Nuggets
"I'm just so overjoyed to have her home, that she's safe", he told reporters outside a courthouse in Columbia, Tennessee, Thursday afternoon.
The two disappeared a few weeks after a student reported seeing Cummins and Elizabeth kissing in a classroom, and law enforcement officials were deeply concerned "about his intentions for her".
"We're going to have to figure out what kind of state of mind she's in, of course, and probably get her some help".
"I feel a little amusing because there were all kinds of indications that there was something a little amusing going on never occurred to me that she was 15 year old, they said she was 22, I thought...yeah", said Peter LaughingWolf. Thomas was reportedly taken to a hospital in California to be checked out; it's not yet known when she'll be able to speak with her family.
Elizabeth Thomas is 15.
March 25 - TBI said more than 1,000 tips had come in, but there were still no credible sightings.
The TBI believes Cummins may have abused his position as Thomas' teacher "in an effort to lure and potentially sexually exploit her".
The teacher and student took off after a student had reported seeing them kissing at school.
Mr Cummins' wife Jill previously made an emotional plea on USA television for her spouse to turn himself in.