Search continues for fiancé Brian Laundrie after coroner determines Gabby Petito's death a homicide

The search for the fiancé of homicide victim Gabby Petito reconvened Wednesday across a vast, alligator-infested Florida wetland, one day after a coroner confirmed that human remains found in a Wyoming national park were those of 22-year-old Petito.

Police in North Port, Florida, have been searching the Carlton Reserve since the family of Brian Laundrie said last week that he vanished while camping in the 25,000-acre wilderness area. Sarasota County's air search team and the Sheriff’s Underwater Recovery Force joined the effort Wednesday.

"SURF Team members are divers called upon to search bodies of water for evidence," the office said in a tweet, adding that the team works "in the most difficult and challenging environments imaginable."

Family members say Brian Laundrie left Sept. 14 to go hiking in the reserve. They filed a missing person report three days later saying they had found his car at the reserve but did not find him. Since then, searchers have used dogs, drones and ATV vehicles to aid the difficult manhunt.

"Please be aware, the Carlton Reserve is a vast and unforgiving location at times. It is currently waist deep in water in many areas," North Port police said in a Facebook post. "This is dangerous work for the search crews as they are wading through gator- and snake-infested swamps and flooded hiking and biking trails."

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Local survival expert Mark Burrow said black bears, coyotes, bobcats, panthers and clouds of gnawing insects also populate the reserve. Everything is wet, almost nothing is edible, and safe drinking water is nowhere to be found, he said.

"If he's down there in the Carlton Reserve, he's living in hell," Burrow said.

Petito and Laundrie left in July on a cross-country adventure that was supposed to end in Oregon late next month. But Laundrie returned alone to their Florida home Sept. 1, and Petito's parents, who live on New York's Long Island, reported her missing 10 days later.

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A nationwide, FBI-led search led to a campground near Wyoming's Grand Teton National Park. The Teton County coroner confirmed the identification and initially determined Petito's death a homicide but provided no specific cause of death pending final autopsy results.

"We extend sincere condolences to Gabby’s family, friends and all the people whose lives she touched," the FBI's Denver office said in a statement. Michael Schneider, FBI special agent in charge, said the bureau and other law enforcement agencies remain dedicated to bringing Petito's killer – or killers – to justice.

The Petito family said it would release a statement when Petito is "home." The Laundrie family, which had drawn the ire of authorities for declining to speak with detectives during the search, issued a brief statement through attorney Steven Bertolino: "May Gabby rest in peace."

Autopsy results: Gabby Petito's death a 'homicide,' autopsy finds; search intensifies for fiance, Brian Laundrie

Police and the FBI have repeatedly pleaded with the public to provide information. Authorities have been wading through an avalanche of tips and even rumors, called in or racing across social media, as to Laundrie's whereabouts. Police in Sarasota, 30 miles northwest of North Port, addressed some of them in a tweet Wednesday.

"Throughout overnight & into this morning, we’ve received numerous inquiries via social media, email & calls," the tweet said. "Despite rumors, #BrianLaundrie is NOT IN THE CUSTODY of our agency at this time. We continue to work w/@NorthPortPolice."

In Okaloosa County, 500 miles northwest of the North Point, the sheriff's department there said they conducted an "extensive search" – that included use of a drone – after grainy video of a trail near Baker, Florida, showed a hiker who looked similar to Laundrie.

"No one – and nothing – of note was located," the sheriff's office said on Facebook. "There are no known possible past or current connections between Laundrie and anyone in this area at this time to follow up on. In the meantime we will remain vigilant and if anything new of significance develops we will share."

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Petito and Laundrie were high school sweethearts in Long Island, New York. Laundrie's parents moved to North Port, and the couple had been living with them before their trip. On Monday the FBI descended on the home, emerging with boxes and towing away a Ford Mustang.

Petito's social media accounts display a romantic adventure in the early days of the journey. But trouble was brewing. In Utah, the Grand County Sheriff's Office on Monday released a 911 call from Aug. 12 in which the caller says he drove by the couple's van and that "the gentleman was slapping the girl.”

Troubling bodycam video of Petito during a subsequent police stop has gone viral, although authorities at the scene took no action other than separating the couple for the night.

Melissa Hulls, a resource protection supervisor at Arches National Park near Moab, heard the possible domestic assault call and was among those responding to the call.

"It’s hard to think about now because I feel like I could've said more to help her," Hulls recently told the Deseret News. “It’s hard not to second-guess myself, and wish I said more, or wish I had found the right words to make her believe that she deserved more."

Contributing: Derek Gilliam, Sarasota Tribune

This article originally appeared on USA TODAY: Search for Brian Laundrie after Gabby Petito autopsy suggests homicide