Bodycam shows Gabby Petito argued with boyfriend before she vanished in Wyoming national park. Video / AP
Police are continuing their desperate search for missing woman Gabby Petito, who is believed to have disappeared in one of the most remote regions of the US.
Petito, 22, was road-tripping across the country with her 23-year-old boyfriend Brian Laundrie when she stopped contacting her family late last month.
Laundrie has been named as a person of interest, but vanished last Tuesday. FBI and police in Florida launched a massive search in a nature reserve three days after he disappeared.
Pepito and Brian Laundrie. Photo / Supplied
Petito last called her family from Grand Teton National Park, which neighbours Yellowstone National Park, on August 25.
The region where Petito disappeared has reignited theories about the "zone of death" in Yellowstone National Park, where academics have suggested criminals could get off without retribution.
A glitch in the US Constitution has made the 80km strip of land difficult to police, with part of it being Idaho and part of it Wyoming.
A 2005 academic paper titled The Perfect Crime, by Michigan State University law professor Brian Kalt, said "there is a 80sq km swath of Idaho in which one might be able to commit felonies with impunity."
Prof Kalt has long called for Congress to redraw the state's judicial boundaries and put Idaho's section of Yellowstone into the District of Idaho.
The entire Yellowstone National Park falls under the federal judicial district of Wyoming, including an uninhabited small strip of land behind the Idaho state border now known as the "zone of death."
The Sixth Amendment in the US constitution requires criminal prosecutions to be heard by a jury from the state and district where the crime was committed.
However, due to the clash of the two states, it is potentially impossible to try someone for murder in the "zone of death" because there is no one to summon for a jury who lives in both the state of Idaho and the district of Wyoming.
Search teams and National Park rangers have been combing through Grand Teton all weekend, with another team reportedly searching Yellowstone.
This police camera video provided by The Moab Police Department shows Gabby Petito talking to police. Photo / AP
"There is a group of park rangers that is searching for Gabby Petito in the back-country of the park," a Grand Teton Park Ranger told the Daily Mail. "This is the park's elite search and rescue unit."
Brian Laundrie vanishes in Florida
The last text message from Petito's phone was warning her family she wouldn't have phone service in Yosemite National Park.
Two days later, her and Laundrie's van was found in Florida.
Reports have since surfaced Laundrie could be in the Mabry Carlton Reserve, a massive 25,000-acre wildlife habitat in Florida.
FBI agents and local police have search teams working their way through the reserve.
The rush to search the reserve came after his family told police "they believe he entered the area".
The North Port Police Department, FBI, and agency partners are currently conducting a search of the vast Carlton Reserve for Brian Laundrie. His family says they believe he entered the area earlier this week. More details when available. pic.twitter.com/I5x7DvQ3Jt
Additional photos from the search for Brian Laundrie around the Carlton Reserve area. If you have seen him please use 1-800-CALL-FBI or submit online at https://t.co/vlIagGqNPE. pic.twitter.com/X5QZmMJhTq
Petito and Laundrie had been travelling the US, documenting their idyllic road trip life on Instagram.
But, it's now been more than two weeks since Laundrie returned to his home in North Port, Florida alone in his girlfriend's van.
Her family then filed a missing-person report on September 11.
North Port Police said Laundrie's parents claim they have not seen their son since Tuesday.
"The attorney for the Laundrie family called FBI investigators Friday night indicating the family would like to talk about the disappearance of their son," the statement said.
"It is important to note that while Brian is a person of interest in Gabby's disappearance, he is not wanted for a crime."
The force said it was now working a "multiple missing person" case.
This police camera video provided by The Moab Police Department shows Gabby Petito talking to police. Photo / AP
North Port police chief Todd Garrison said its conversation with the family "is complete."
"Once we have details, a statement will be made," he tweeted. "We ask for calm!"
The couple embarked on their journey across the US in July, departing New York on the east coast, and posting photos of magnificent views of the American West and themselves smiling happily next to their small white van.
In one YouTube video published during their trip, Petito and Laundrie are shown kissing tenderly, enjoying a sunset together and strolling on a beach.
However, in August, police in Utah responded to a domestic violence report involving Petito and Laundrie.
Police body cam footage published by US media showed a distraught Petito saying she had had an altercation with Laundrie.
Speaking to a police officer after their van was pulled over, Petito was seen crying and saying she struggles with mental health problems.
Joe Petito, Gabby Petito's father, has appealed for anyone with information on her whereabouts to contact the authorities, adding that an anonymous tip line has been set up.
