The manhunt for Brian Laundrie continues in connection with the death of Gabrielle Petito, whose remains were found in a Wyoming park after disappearing in late August. Laundrie, who was her boyfriend, has been in hiding after returning to his home in Florida after having been on a months-long road trip across the country with Petito.

While Laundrie is still not officially considered a suspect in Petito’s death, which was ruled a homicide, federal authorities issued an arrest warrant alleging that he “knowingly and with intent to defraud, used one ore more unauthorized access devices, namely a Capitol One Bank debit card.”

The search for Laundrie is entering its third week, and authorities have been met with various challenges when it comes to locating the young man. He was believed to have left for the Carlton Reserve on Sept. 17, according to his parents, but indications suggest he could also be hiding out in a different location.

CNN interviewed several experts who indicated that the conditions in South Florida make it more difficult to find forensic evidence. When Laundrie left his parents’ home, he told his parents he was headed to the Carlton Reserve and left behind his cell phone and wallet.

Former FBI special agent and associate professor in the department of criminology at the University of South Florida, Bryanna Fox said Laundrie’s leaving those two items behind “may mean there’s very little digital or forensic evidence for authorities.” The phone would have allowed investigators to know who he is communicating with and where he has been. The wallet would have shed light on where he is spending money.

Fox also pointed out that “unlike other fugitives or people that are missing,” it is usually believed they are in a populated area, but that in Laundrie’s case, “it looks like he attempted to maybe go off the grid and is not living in society,” which makes it more difficult to locate him.

She also stated that tropical conditions “are among the harshest on forensic evidence.”

It also recently came to light that Laundrie purchased a burner phone on Sept. 14 “with an older woman,” according to TMZ. The report states:

Sources connected to the manhunt for Laundrie tell TMZ … FBI agents recently visited an AT&T store in North Port, FL — where Laundrie’s parents live — and seized surveillance footage.

[TMZ is] told Brian allegedly went to the store September 14 with an older woman and purchased the phone before they left.

This is important in the chronology of events, because Sept. 14 is the day Laundrie supposedly set out for the Carlton Reserve, according to his parents, who reported him missing on Sept. 17. Steven Bertolino, the attorney representing the Laundrie family, confirmed the report:

“To my knowledge, they did purchase a new phone and it’s the same phone that Brian left home and which the FBI is in possession of.”

Other groups have also joined the manhunt. Some believe Laundrie might have fled to Fort De Soto Park, located in Pinellas County, Florida. It was later discovered by the authorities and Duane “Dog the Bounty Hunter” Chapman that he and his parents had camped there on Sept. 6 and 7.

Michael Hadsell, the Peace River K9 Search and Rescue President, said told SNN News that he did not believe the fugitive could be hiding in Fort De Soto at first, but after searching in the area, believed that “we may be really into something.”

Hadsell’s team joined Dog the Bounty Hunter last week and has been taking boats to search around several islands, following up on tips from the public. He said:

“We did find some campsites, we did find some evidence of kayaks near the campsites so it is possible that Brian’s out there.”

He indicated that his K9 team has to use different methods of searching for Laundrie, because his parents have not been helpful. He said:

“The parents as you know are being uncooperative, so we don’t have any sent articles or anything from Brian to be able to use it as a target odor for our dogs to work on.”

Hadsell said that because they have no articles of clothing from Laundrie’s family, they have to go by “general human scent.”

He explained that his dogs are “trained to work on odor from the boat,” and that “if there is any human odor being produced from the island, the dogs will alert, and then we’ll send teams to go check it out.”

Another development surfaced on Friday when a hiker claimed to have encountered Laundrie while hiking on the Appalachian Trail in North Carolina. The New York Post reported that the hiker, who is also an engineer from Florida, was “adamant” that he conversed with the fugitive on a deserted road on Saturday morning. The authorities have received tips that Laundrie has been spotted in that area, and he was known to have lived there by himself for several months.

Davis claimed that the man approached him to ask for directions to California using “only back roads.” Davis said the man was acting “skittish” and said he and his girlfriend had “got in a fight,” but that she called him and said she loved him. He claimed to be traveling to California to see her.

However, the veracity of his claims, similar to others that have been made, has not been confirmed.

Despite the difficulty involved in tracking Laundrie down, there are some who contend that he will be caught eventually. Lenny DePaul, a former 30-year veteran with the U.S. Marshals, believe the fugitive is still alive and will be apprehended at some point.

On Thursday, he told the New York Post:

“I personally think he could be anywhere. It doesn’t matter. Mexico. He can be on a boat sitting off the coast of Cuba. It doesn’t matter. He’s gonna mess up. He’s going to make the mistake.

“Right now they’re chasing a ghost,” DePaul continued. “But he’s sleeping with one eye open.”

The former marshal also suggested that the authorities might be applying pressure to Laundrie’s parents, as well as his friends and associates.