Late Wednesday night, the tip that TBI investigators were desperately hoping for finally arrived.
It came from a caller who told investigators that Cummins and the teen, the subject of an Amber Alert, might be living in a mountain cabin near Cecilville, Calif., a onetime mining town about 100 miles south of the Oregon border.
Tennessee investigators coordinated with the Siskiyou County Sheriff's Office, which found the silver Nissan Rogue belonging to Cummins and kept the vehicle under surveillance for several hours in one of the northernmost parts of California.
And then, at daybreak Thursday, the authorities captured Cummins and rescued the teen.
Authorities said Elizabeth was physically unharmed, but her attorney said the teen has "suffered severe emotional trauma and that her process of recovery is just beginning," according to the Associated Press.
Anthony Thomas, the teen's father, told "Good Morning America" on Friday that he thinks his daughter was brainwashed. When authorities closed in on Cummins and Elizabeth at the remote cabin, Sheriff Jon E. Lopey told the AP, Elizabeth was "laughing, crying and acting stoic."
The teen didn't exhibit any anger toward Cummins, Thomas said. "I didn't observe any emotional distress. She didn't act like a rescued person would act."
Siskiyou County Sheriff's Sgt. Mike Gilley told CNN that Cummins expressed relief after his capture. "I'm glad this is over," Cummins said, according to Gilley.
By the weekend, the girl had been flown back to Tennessee and reunited with her family.
Meanwhile, investigators from TBI, the FBI and the Maury County (Tenn.) Sheriff's Office traveled to Northern California to continue their investigation. Inside the cabin, they found a single sleeping pad, clothing and two loaded guns, authorities said.
Cummins - who is being held by the Siskiyou County Sheriff's Department without bond - faces federal and state charges that "could keep him behind bars for many years," TBI director Mark Gwyn said.
Once Cummins is extradited to Tennessee, he will be charged with sexual contact with a minor and aggravated kidnapping, authorities said.
Acting U.S. Attorney Jack Smith said his office had also filed a federal charge of transportation of a minor across state lines for criminal sexual intercourse, which carries a minimum 10-year sentence.
"I'm very happy," Anthony Thomas, Elizabeth's father, told NBC affiliate WSMV. "She's probably going to be hungry."
He added: "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. Maybe a long road, but at least we've got her back."
The teenager's return was "wonderful news for our community," the Maury County Public Schools District said in a statement. "Thanks go to all who have kept the message of finding Elizabeth Thomas and working on her safe return as top-of-mind throughout the nation."
The saga began in March, after Cummins handed over the title of his SUV, put up some other personal effects and walked out of a loan office with $4,500 in cash.
The high school health teacher was on the verge of losing his job and his freedom after he'd been spotted kissing a 15-year-old student, according to the TBI. A criminal investigation was swirling, and authorities believed Cummins, who was armed with two handguns, had little left to lose.
The $4,500, investigators said, helped the pair elude authorities during a manhunt that made national headlines. TBI investigators said Cummins, who had been the teen's health teacher at Culleoka Unit School, may have planned to abduct Elizabeth well before he picked her up at a Shoney's restaurant in Columbia, Tenn.
"Investigative efforts have revealed a troubling pattern of behavior by Tad Cummins, suggesting the 50-year-old may have been abusing his role as a teacher to groom this vulnerable young girl for some time in an effort to lure and potentially sexually exploit her," the agency said in a statewide Amber Alert issued the day after the girl disappeared.
"Having now been on the run for more than five days, Cummins may have taken her, frankly, anywhere," the agency said last month.
On March 13, video surveillance at a Columbia gas station showed Cummins filling up the same Nissan Rogue that was eventually spotted in California. A short time later, investigators say, he drove to the Shoney's restaurant, where Elizabeth had been dropped off by a friend.
Investigators said they think he manipulated her into leaving with him; but he wasn't authorized to take a minor, and she wasn't old enough to consent. That afternoon, investigators say, they determined Elizabeth was 80 miles away in Decatur, Ala.
After the pair's disappearance, investigators said they received hundreds of tips from 24 states, but not enough information to tighten the dragnet despite a multistate manhunt and Cummins's addition to Tennessee's most-wanted list. The TBI said Cummins might be keeping Elizabeth out of sight of authorities, possibly sleeping in his car or in a rural community.
Last month, the agency released new images of Cummins in an effort to keep the case in the spotlight. The pictures were from a week before Cummins and Elizabeth disappeared, and they showed him wearing a camouflage cap and pushing a shopping cart at a store.
Tips continued to pour in, but they led nowhere - until the call about Cummins's car.
"What happened in California this morning, however, proves it only takes one person to lead to a successful end," said Gwyn, the TBI director. "We are extremely thankful the hard work of all partners in this search has paid off. We're also grateful for the public's support and vigilance throughout this search effort."
Jason Whatley, a lawyer for the teen's family, told reporters in Tennessee that the phone call confirming that Elizabeth had finally been found safe was "surreal."
"We are beyond elated," he said.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)