UPDATE 5:15 PM FRIDAY: The wife of a man sought in the kidnapping of a 15-year-old Maury County girl pleaded Friday afternoon for her husband to turn himself in.

"Tad, this is not you," Jill Cummins said during a Friday afternoon press conference staged at the Maury County Sheriff's Office. "This is not who you are. We can help you get through this, no matter how far you've gone or what’s happening right now. God’s grace is sufficient for you and he wants you to come home. Your family wants their poppy back."

Her voice breaking, Jill Cummins added: "Please do the right thing and turn yourself into the police and bring Beth back home."

Tad Cummins and Elizabeth Thomas have not been seen in four days. An AMBER alert has been issued for her.

Prosecutors have authorized a new charge against Cummins - aggravated kidnapping, said District Attorney General Brent Cooper.

Josh DeVIne, TBI spokesman, said Friday at the press conference that the agency so far has received about 175 tips. That's "shockingly" low, he said.

"We have no idea where these individuals could be right now," he said. "This is a dire situation for this girl right now."

DeVine said the TBI hoped hearing from his wife directly would sway Cummins.

Cummins has firearms, which raises further concerns for investigators, DeVine said.

VIDEO: Full TBI news conference on search for Tad Cummins and Elizabeth Thomas

Jill Cummins told reporters she was "deeply troubled" by her husband's disappearance with Elizabeth. She said she had no idea he would do anything like this.

If convicted of aggravated kidnapping, Cummins could face eight to 12 years in prison, Cooper said. The prosecutor said if Cummins provides information that leads to the girl's return or if he voluntarily releases her, that would weigh in his favor legally.

"His actions can determine how serious the outcome is. I urge Mr. Cummins to pick up the phone," Cooper said.

Anyone who may have interacted with either Thomas or Cummins before their disappearance should call TBI at 1-800-TBI-FIND.

The TBI expects soon to release new photos of Cummins taken just a few days before he and the girl disappeared, DeVine said.

It will also be adding Cummins to the agency's Top 10 Most Wanted list.

PREVIOUS STORY: The 15-year-old victim of an ongoing AMBER Alert, and the 50-year-old man she may be with, could "frankly, be anywhere" at this point, the Tennessee Bureau of Investigation said Thursday.

Elizabeth Thomas, 15, is believed to be with an ex-teacher from her school, Tad Cummins. Authorities say he is armed with two handguns. The pair may be driving a Silver Nissan Rogue with Tennessee tags 976ZPT.

“It’s absolutely important that everyone in this nation know about these individuals because frankly, they could be anywhere right now,” TBI spokesperson Josh Devine said during an update Thursday afternoon.

The two were last seen on Monday morning in Columbia, Tennessee; however, investigators have info placing Thomas in the area of Decatur, Alabama on Monday afternoon.

Since issuing an AMBER Alert Tuesday evening in Tennessee and Alabama, TBI said it has received just 125 tips.

“If 125 leads sounds like a low number, it is. It is the lowest number of leads for an AMBER Alert that we’ve seen go this long. It is alarmingly low,” Devine said. He explained that it indicates the pair may be out of the view of the general public or outside the area across the southeast that have been notified.

Former Knoxville Police Chief Phil Keith, who also used to run the national AMBER Alert system, weighed in on the case Thursday.

Keith said the more their photos are kept in the public eye, the more likely they will be found.

"When AMBER Alerts are issued, the child is recovered in a very high percentage, 98 or 99 percent," Keith said.

He urged people not to give up hope.

"The least little bit of a hint can save that child’s life," he added.

He said the two could be anywhere so it's important for officers to stay vigilant and for people to stay aware of their surroundings.

"Anyone that has children and has a love for children they are acutely tuned into those kinds or messages so you have more eyes looking," Keith said.

<p>The AMBER Alert poster for 15-year-old Elizabeth Thomas and 50-year-old Tad Cummins. Anyone who see them or their vehicle should call 911. </p>

On Thursday, TBI issued a second nationwide BOLO so that every agency knows about the alert.

“Law enforcement can not do this alone. We need the public to keep an eye out, pay attention," Devine said.

TBI also revealed Thursday that it has found a troubling pattern of behavior suggesting Cummins may have been abusing his role as a teacher to lure and potentially sexually exploit Thomas.

Cummins was a teacher at Culleoka Unit School, where Elizabeth went to school.

District Attorney General Brent Cooper have said that Cummins is wanted in connection to an alleged sexual interaction between Cummins and a minor. The school district suspended him when those allegations surfaced and he was fired on Tuesday.

Investigators have put together a timeline placing Cummins and Thomas in the same area just before their disappearance on Monday:

• 7:30 - 7:45 a.m. Monday: A friend of Elizabeth Thomas drops her off at the Shoney's in Columbia, Tenn.

• 8:32 a.m.: Surveillance video appears to show Tad Cummins at a nearby Shell station

• 12:41 p.m.: Maury County Sheriff's Department enters Thomas as 'missing' in NCIC, nation's law enforcement internal communications database

• 3:06 p.m.: Information places Thomas in the area of Decatur, Ala.

Anyone who may have interacted with either Thomas or Cummins before their disappearance should call TBI at 1-800-TBI-FIND.

If you spot the suspect vehicle and can verify the license plate to be TN 976-ZPT, authorities say to call 911.