Brian Laundrie Could Be in Florida Swamps 'for Months': Police

Skilled outdoorsmen such as Brian Laundrie could be out in Florida swampland "for months," police have suggested, as separate searches continue for him and Gabby Petito, his fiancé who went missing on their YouTubed campervan trip.

At daybreak on Sunday, officers will resume the search for Laundrie in the 25,000-acre Carlton Reserve near North Port. Meanwhile, thousands of miles away, the FBI continues to search for Petito in a mountainous national park in Wyoming.

Laundrie, 23, had returned to their shared North Port home alone on September 1, before Petito's family reported her missing. He is a person of interest over Petito's disappearance but is not wanted for any crime, police say.

Laundrie, who has refused to talk with investigators, was reportedly last seen on Tuesday, telling family he was going on a hike.

Petito's family has insisted Laundrie "is not missing, he is hiding."

The search for Laundrie was paused about 7:45 p.m. on Saturday.

Earlier that day, North Port Police Department spokesman Josh Taylor said the search for Laundrie could take "a long time."

"I don't know how frequently if he would come out here and do day-long hikes or whatever, you could be out here for months if you wanted," Taylor told the New York Post.

"Were we trying to keep an eye out kind of where he's at so that when needed we could potentially reach him? Yes. But our focus was putting resources on trying to find Gabby."

More than 50 local police officers, FBI agents and members of other law enforcement agencies have joined the search for Laundrie.

Authorities are using drones, all-terrain vehicles and search dogs—using Laundrie's clothing to provide a scent.

Discussing the Carlton Reserve terrain, he added: "It's muddy, it's wet, there are a few unpaved dirt roads that are out there basically running along the power lines, you know its a place that people hike, there are mountain biking trails out there."

Police fear Laundrie could be a danger to himself or others. It is not known whether or not he is armed.

After his family reported him missing on Friday, police released a statement on how they had been "frustrated" by developments.

"For six days, the North Port Police Department and the FBI have been pleading with the family to contact investigators regarding Brian's fiancée Gabby Petito. Friday is the first time they have spoken with investigators in detail," it read.

Protests have taken place outside the Laundrie family home, with demonstrators shouting on Friday, "Where's Gabby?"

Laundrie's sister, Cassandra, told ABC News that Petito "is like a sister and my children love her and all I want is for her to come home safe and sound and this be just a big misunderstanding."

Instagram and YouTube posts indicate that the couple made stops in Kansas, Colorado and Utah. But somewhere in Wyoming, Petito's family lost contact.

Ten days after Laundrie returned to the couple's shared home in North Port, with the van but without Petito, her family reported Petito missing.

On Wednesday, Laundrie was officially named a person of interest in her disappearance.