ORLANDO - The police and Federal Bureau of Investigation (FBI) agents planned to resume their search of a swampy Florida wilderness for Ms Gabby Petito's fiance on Wednesday (Sept 22), one day after the local coroner in Wyoming identified a body found there as the missing 22-year-old travel blogger.

Police have called Mr Brian Laundrie, 23, a "person of interest" in the case, which has captivated Americans since Ms Petito's family reported her missing on Sept 11.

Ten days earlier, Mr Laundrie had returned home to North Port, Florida, without her from a cross-country road trip.

Mr Laundrie has not been seen since Sept 14, when he purportedly left the family home in North Port with plans to hike alone in the nearby Carlton Reserve wilderness area.

The North Port police say they learned from Mr Laundrie's family only on Friday that he had been gone for three days.

At nightfall on Tuesday, police and FBI agents broke off their efforts to find Mr Laundrie in the vast, alligator-infested reserve, which has some 129km of hiking trails. Other sections are nearly impassable.

A North Port police spokesman said they would return there early on Wednesday to resume the effort.

Search teams found Ms Petito's body on Sunday in a remote area of Bridger-Teton National Forest, in western Wyoming, less than 300m from where, on the evening of Aug 27, a pair of travel bloggers recorded on video what appeared to be the couple's white Ford Transit van parked along a dirt road.

In identifying her remains, the Teton County Coroner's Office ruled Ms Petito's death a homicide, but did not make the cause of her death public.

"The FBI and our partners remain dedicated to ensuring anyone responsible for or complicit in Ms Petito's death is held accountable for their actions," FBI Denver special agent in charge Michael Schneider said in a statement.

Ill-fated trip

Ms Petito and Mr Laundrie left her home state of New York in late June or early July, heading west in the van with plans to visit US national parks and document the trip on social media.

Witnesses last saw Ms Petito on Aug 24 as she left a Salt Lake City hotel. She posted her final photo the next day.

Ms Petito's family believes she was headed to Grand Teton National Park when they last heard from her. Her body was found at the edge of the park, near the Spread Creek Dispersed Camping area.

On Monday, investigators served a search warrant on the Laundrie family home. They were seen loading cardboard boxes into a van and towing away a silver Ford Mustang.

In seeking the search warrants, investigators cited an Aug 27 text from Ms Petito's phone to her mother, Ms Nicole Schmidt, which describes getting calls and voice messages from "Stan", Ms Petito's grandfather.

Ms Schmidt told investigators the text was odd because her daughter would not usually refer to her grandfather by his first name. Ms Petito's family has said a second text message also seemed suspicious.

Last week, police in Moab, Utah, released body camera video of an Aug 12 encounter that two of their officers had with Ms Petito and Mr Laundrie during a traffic stop.

Ms Petito sobs in the video as she describes a quarrel with Mr Laundrie, and admitted that she slapped him. The officers did not detain the couple but insisted they spend that night separately, Ms Petito in the van and Mr Laundrie at a hotel.

That same day, a caller told emergency dispatchers that he had seen Mr Laundrie slapping and hitting Ms Petito, according to audio of the 911 call released by police.