The investigation into the alleged abduction of a 15-year-old Tennessee girl by her 50-year-old former teacher is in its second week

As the investigation into the alleged abduction of a 15-year-old Tennessee girl by her 50-year-old former teacher enters its second week, officials say the pair seems to have gone “off the grid.”

“We still [have a lack of] information, lack of quality leads and a lack of quantity leads,” Tennessee Bureau of Investigation spokesman Josh DeVine says of the disappearance of Mary Catherine Elizabeth Thomas.

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.

Tad Cummins, a health science teacher at her high school, allegedly picked her up before she disappeared.

DeVine says investigators were able to place Thomas in Alabama last week, but they have not been able to locate the high school freshman since.

Investigators have received more than 450 tips, DeVine says.

“We firmly believe that they are essentially off the grid and Cummins has her out of public view,” he says, urging the public to search their properties, local camp grounds, rural areas and parking garages.

A warrant has been issued for Cummins’ arrest on charges of aggravated kidnapping and sexual contact with a minor, according to the TBI. The latter claim stems from an alleged sexual interaction between him and Thomas in January on school property.

“It’s been a week, and anything is possible,” DeVine tells PEOPLE. “They might have changed their appearance or changed their vehicle. We’re trying to cast the widest net possible.”

“She’s a high school freshman. He was a teacher accused of kidnapping her. Let’s find her now!” DeVine tweeted on Saturday. Cummins’ wife and Thomas’ family have also issued emotional pleas.

On Monday, investigators released new photos and surveillance footage of Cummins in a local Wal-Mart days before he allegedly kidnapped Thomas.

In one of the videos, Cummins appears to be shopping in the beauty section — specifically an aisle for hair dye. DeVine could not confirm what Cummins purchased that day.

Mary Catherine Elizabeth Thomas and Tad CumminsCredit: TBI
Mary Catherine Elizabeth Thomas
| Credit: Courtesy Tennessee Bureau of Investigations
Mary Catherine Elizabeth Thomas and Tad CumminsCredit: TBI
Tad Cummins
| Credit: Courtesy Tennessee Bureau of Investigations

Thomas was picked up from her home the morning of March 13 by a female friend, investigators say, and was last seen at 7:45 a.m. at the Shoney’s. By 12:41 p.m., she was missing.

Cummins was seen after 8 a.m. that day on surveillance camera at a local gas station adjacent to the Shoney’s. Authorities believe he got Thomas after putting gas in his car.

The Thomas family’s attorney told PEOPLE that hours before her alleged kidnapping, Thomas told her family she was meeting a female friend — but to call the police if she went missing.

AMBER Alerts have been issued in both Alabama and Tennessee, along with a national BOLO Alert.

Cummins is believed to be “armed and dangerous” and carrying two handguns, DeVine says. He has no criminal history in Tennessee, according to authorities.

The Maury County Public School District, where Cummins worked, released a statement last week announcing his termination.

“I think that every day that goes by, we get more concern for [Thomas’] well-being,” DeVine says.

“We want her home as quickly as possible, and the fact that she’s not is certainly frustrating,” he says. “But the reality is we remain hopeful, because all it takes is one person who knows what to be looking for and what to do when [they] see it.”

DeVine urges anyone who believes they spot Cummins or Thomas to not approach them and instead keep an eye on them while calling 911.

Thomas was last seen wearing a flannel shirt and black leggings. She is 5 feet 5 inches 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 Thomas should call the TBI at 1-800-TBI-FIND.