Brian Laundrie is still missing almost a month ago since his parents said he went on a hike near their Florida home.

But even though not much is still known about his whereabouts, experts say that there's still hope that they will find Laundrie sooner or later.

Brian Laundrie can't make a single mistake or he'll get caught

Bryanna Fox, a former FBI special agent and associate professor in the department of criminology at the University of South Florida, said that one mistake could lead authorities to Laundrie.

"In other words, he has to be perfect and make zero mistakes. Law enforcement, to be able to find him, they either have to find one clue or catch one mistake he made and that could blow the whole case open," she told CNN.

Several factors are complicating the search for Brian Laundrie

However, Fox also acknowledged the fact that it's been a struggle trying to locate Laundrie because he left the two key items that could've otherwise determined his movements.

Last week, reports revealed that Laundrie left his home without his wallet and cell phone. But he later purchased a burner phone from a nearby AT&T store.

The phone would've determined Laundrie's location and his wallet would've revealed his purchases. But without these two key items, the search for Laundrie has been a drag.

Read Also: Brian Laundrie's Family Denies Helping Son To Escape As Protesters Surround Property, Shouting 'Justice For Gabby Petito'

Fox added that most fugitives and missing persons tend to stay in populated areas. But the same cannot be said about Laundrie. The former FBI special agent is convinced that Gabby Petito's fiancé decided to go off the grid.

Additionally, tropical conditions are also playing a huge part on the case because the more days pass, the odds of finding forensic evidence becomes slimmer.

Michelle Jeanis, an assistant professor at the University of Louisiana in Lafayette's Department of Criminal Justice, said that there also needs to be a balance between tips and actual evidence.

New witness claims to have seen Brian Laundrie on a trail in North Carolina

Since a lot of people have become invested in Laundrie's disappearance, they have been providing the FBI with tips and information. However, if this information doesn't direct the officers to Laundrie, then it could just prolong their search.

In fact, a new witness has come forward and said that he encountered Laundrie near the Appalachian Trail in North Carolina over the weekend, according to New York Post.

Dennis Davis said that he's confident it was Laundrie that he encountered after Dog the Bounty Hunter's daughter sent him an audio file of Laundrie's voice. He said that it sounded exactly like the voice of the man that he saw on the trail

The witness said that the man, who he believes is Laundrie, pulled up next to him to ask for directions to California using only back roads.

He added that the man also claimed to be looking for his way to California after his girlfriend called him and said that she loves him.

Supporters want to know what happened to Gabby Petito in her final days

A lot of people want to find Laundrie because they want to know what really happened between him and Petito during the final days of their cross-country trip.

Petito stopped posting photos and videos on her Instagram account at the end of August, and this left her family feeling worried. Their concerns grew after they learned that Laundrie returned home without Petito on Sept. 1.

The 22-year-old vlogger's body was found in Wyoming on Sept. 19, and her death was later ruled as homicide, according to Deseret News.

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