NORTH PORT, Fla. (NewsNation Now) — Search teams headed back into the Carlton Reserve Saturday to continue the search for the fiance of Gabby Petito, the young woman who authorities say was killed while on a cross-country trip with him.

Petito’s remains were found last Sunday near Grand Teton National Park in Wyoming.

Brian Laundrie, who is believed to be the last person to see Petito alive, refused to cooperate with authorities before his disappearance. His family told investigators he went hiking in Carlton Reserve and never returned.

Law enforcement officials have been searching for a week, and still, there is no trace of the 23-year-old’s whereabouts.

North Port Police received reports of gunshots on Friday around 7 p.m., only to find out it was a false alarm. A police spokesman said they got a call from an unknown phone number about gunshots in the area, but police found no such evidence after going inside and talking to neighbors.

The Laundrie family attorney shared new information Friday, saying Brian had left home without his wallet or cellphone and said his parents are concerned he might hurt himself.

On Saturday, multiple agencies began searching the unforgiving terrain of the 25,0000-acre Carlton Reserve again, looking for Brian.

North Port Police Department Commander Joe Fussell said they’re not wasting their time with the search.

“We’re doing our due diligence to find Brian in an area where intelligence led us, that he could possibly be in,” Fussell said. “It’s upon us to make sure we search this area as best we can, as massive as it is, to try to find Brian.”

The conditions they’re exploring are difficult.

“We’re looking through wooded areas, bodies of water, swampy areas, and we’re deploying the resources to be able to do that,” Fussell said. “We have air units, drones, swamp buggies, airboats, multiple law enforcement agencies, and more.”

Brian reportedly went into the wooded reserve last Tuesday, which is about 75% underwater, according to experts.

Conditions are hot and muddy. If Brian is in there, experts say finding food, water, and shelter must be difficult.

NewsNation affiliate WFLA spoke with a self-proclaimed outdoor expert, Darry Jackson, who said he’s gone through survival school. He said if Brian is still in the wooded reserve, he’s probably in a world of pain.

“I think by now, he would be in such discomfort,” Jackson said. “He would give himself up because he is going to want food; he’s going to want shelter.”

He went on to say, “I would be surprised if he is there, and if so, I would be surprised if he was alive.”

“Dog the Bounty Hunter” visited the Laundrie family home on Saturday afternoon.

The reality TV personality, whose real name is Duane Chapman, pulled up to the North Port home of Christopher and Roberta Laundrie around 4:30 p.m. and knocked on the front door. No one answered.

When asked why he was there, Chapman told a NewsNation reporter, “come on, you know,” and implored the public to share tips by calling 833-TELL-DOG.

NewsNation affiliate WFLA contributed to this report.