NEW LEAD: Hiker claims he saw Brian Laundrie near Appalachian Trail

A Florida man hiking the Appalachian Trail claims he saw Brian Laundrie driving in a white pickup truck around 12:30 a.m. ET on Saturday in Tennessee near the North Carolina border.

Dennis Davis, who spoke to a number of news outlets on Saturday including Fox News Digital twice, said it didn't at first register that the driver may have been Laundrie, but after the encounter, he looked up photos of the fugitive wanted on debit card fraud charges, and he then felt convinced enough to call in the sighting to FBI twice, as well as 911 operators in Tennessee and North Carolina.

"There is no doubt about it. That was Brian Laundrie I was just talking to. 100%. Not a doubt in my mind," Davis said of the encounter after he looked up both a portrait and profile shot of Laundrie on his phone.

Laundrie is on the lam and is wanted on bank fraud charges after his 22-year-old fiancée, Gabby Petito, was found dead in Wyoming last month.

RELATED: As time ticks by, more questions than answers in search for Brian Laundrie

Davis and some other hikers were going to leave a car at the Northern Terminus of the Application Trail, and he was going to sleep at the trailhead Friday night. He accidentally passed a parking lot near the trail and was going to make a U-turn on Waterville Road when "a vehicle approached" from behind him and flashed its headlights as if signaling to Davis that he could complete his U-turn.

After completing his U-turn, he was driving back in the direction of the pickup truck when the man driving it stuck his hand out of the vehicle.

"I pulled up alongside of the vehicle," Davis explained. "…I rolled my window down and I started talking with the gentleman. I could tell right away that something wasn't right with him."

His immediate thought was that the driver was "on drugs at first," but after reflecting on it, Davis said he "looked mentally shot." Davis added that the driver "didn't look dirty at all."

RELATED: Gabby Petito: Timeline of 22-year-old woman's disappearance, death

The driver then told Davis that he was lost and was trying to get to California after getting in a fight with his girlfriend.

"He said me and my girlfriend had a fight, and man, I love her, and she called me, and I need to go out to California to see her," Davis explained. Davis then told the driver to take I-40 West, but the driver said no and that he would rather stay on Waterville Road by the Pigeon River.

"He said, ‘No, I think this road that we're on — I'm going to take it to California,'" Davis said.

RELATED: How Brian Laundrie's behavior could provide clues about his disappearance

The hiker thought about the encounter afterward as he started driving again and began to wonder whether it was Laundrie.

"So I got to the next spot where I was going to park and I pulled open my phone and I started looking through pictures. And the thing when I was talking to him which really stood out to me was: He had a very full but short, very thick, dark, black beard and mustache. And so when I parked my car and I pulled up the picture of him on the internet…and there was that beard and mustache," Davis said.

At that point, the hiker was 95% sure he had seen Laundrie and called the FBI. When he got off the phone with the FBI, he looked at another profile shot of Laundrie and then felt 100% convinced that he spotted the fugitive, at which point he called the FBI a second time, as well as Tennesee and North Carolina police.

RELATED: ‘Grabbed me with his nail’: Gabby Petito describes Utah fight with Brian Laundrie in newly-released bodycam

The Haywood County, North Carolina, Sheriff's Office said on their dispatch that they received a call from Davis around 2:40 a.m. Saturday near the Waterville exit, where he had cell service again to look at more photos of Laundrie. He related the story to police, and the sheriff's office dispatches two to three deputies to the area. Deputies came across three idle vehicles, which they ran, but all came up inconsequential and were likely hikers' vehicles.

The sheriff's office, which said it has received about 10 more sightings and calls between Saturday and Sunday, sent a team to mile marker seven near the Waterville exit. Tips have picked up within the last few days but none have been as specific as Davis'. One woman called in a possibly Laundrie sighting saying she saw a man with skinny legs.

As of Sunday morning, neither the FBI nor the police had contacted Davis. The FBI, nor several police departments and sheriff's offices in the areas of Tennessee and North Carolina Davis described, responded to inquiries from Fox News.

People have reported many potential Laundrie sightings across the country as his whereabouts remain unknown in the high-profile case. Last month, people reported possible sightings in Mobile, Alabama, where a man was found dead near a local Walmart store, and in trail camera footage from Baker, in Okaloosa County, Florida.

RELATED: Gabby Petito update: Everything known about disappearance, death, autopsy

One man who informed Fox News of a since-debunked potential Brian Laundrie sighting in New Jersey last month said "it was like pulling teeth to get law enforcement to act on the [sighting]," and that some officials were "rude" on the phone.

Xander Mcdouall, the co-owner of a bounty hunting team called Predator Hunter Nation, confirmed to Fox News that they spoke to Davis and are searching the area he described.

Investigators working with Duane "Dog the Bounty Hunter" Chapman are also honing in on portions of the Appalachian Trail in North Carolina as they continue their search for Laundrie. Lyssa Chapman, Chapman's daughter, said her father's team is "working on confirming" several new leads in a Saturday tweet.

As the manhunt for Laundrie forges on, people have claimed to have seen the 23-year-old avid hiker in Watauga County, North Carolina, according to multiple reports. Users in a private Facebook page, Appalachian Classifieds, described how people were "reporting seeing Brian Laundrie in Boone, NC," according to the Watauga Democrat.

RELATED: FBI agents eye camper outside Brian Laundrie's family's home

The Watauga County Sheriff’s Office told local affiliate FOX 46, "We were looking into these claims, but nothing has been verified." Sheriff Len Hagaman told Fox News that the department was "only monitoring social media reposts – nothing validated."

The Appalachian Trail as a whole is "the longest hiking-only footpath in the world, ranging from Maine to Georgia," according to the Appalachian Trail Conservancy. It spans more than 2,193 miles and across 14 states. In North Carolina alone, the Appalachia Trail encompasses 96.4 miles and reaches elevations of up to 5,498 feet.  

Both Laundrie and Petito have allegedly hiked parts of the Appalachian Trail. In March, Petito shared a photograph on Instagram with a geotag for the Appalachian Trail in Georgia.

And a woman who says she was one of Petito’s best friends, Rose Davis, told PEOPLE that Laundrie "lived in the Appalachians by himself for months."

Laundrie and Petito were traveling across the country in a Ford Transit van over the summer before Laundrie returned to his home in North Port, Florida, on Sept. 1 in the van without Petito. Petito's parents reported her missing 10 days later on Sept. 11. Laundrie's parents reported Laundrie missing on Sept. 17 but said the last time they saw him was on Sept. 14.

After Petito’s missing persons’ report was filed on Sept. 11, Laundrie would not cooperate with the police investigation, officials said. The Laundries’ attorney released a statement on Sept. 14, in which he announced he had advised his clients to remain "in the background." The family revealed three days later that they had not seen him since Sept. 14.

Petito’s body was discovered near Grand Teton National Park in Wyoming on Sept. 19. A Teton County coroner ruled the death a homicide but has not yet announced the cause. 

Fox News' Stephanie Pagones, Michael Ruiz and Kathleen Reushcle contributed to this report.