Gabby Petito Update: Murder Location Key For Prosecuting Killer, Say Authorities Amid Brian Laundrie Manhunt

As the search for Brian Laundrie drags on, the federal authorities continue to investigate the death of Gabby Petito. Officials are trying to figure out if Petito was killed where her body was found or if she was moved after the murder.

Law enforcement sources exclusively told TMZ the location of the murder was key for prosecuting the killer. They reportedly said the case could be more complicated depending on where the 22-year-old YouTuber was killed.

The Long Island native was found dead at a national park – which was in the vicinity of Grand Teton National Park and the Bridger-Teton National Forest Service – in Wyoming on Sept. 19.

The sources said the body was found in federal land, which was why the FBI is running point in the case. However, if Petito was not killed on federal land, then the case would move over to the state authorities. Sources close to the investigation told TMZ if authorities fail to determine where Petito was killed, then the location where her body was found will become the default murder spot. Since it's on federal land, the U.S. Attorney would prosecute the accused killer.

However, state authorities reportedly believe Petito's body was moved there.

Meanwhile, Laundrie – who is the only one named as a person of interest in the case – is still unaccounted for. New details about the 23-year-old's movement were revealed Wednesday after authorities found remnants of a campsite that appeared to have been recently used in Florida's Carlton Reserve. The 24,565-acre park is currently closed to visitors, CNN reported.

Meanwhile, the family attorney of Petito's fiancé said Laundrie's father, Christopher, would be assisting authorities in the search for his son.

"Chris Laundrie was asked to assist law enforcement in their search for Brian at the preserve today," Steve Bertolino said. "Since the reserve has been closed to the public, Chris has not been able to look for Brian in the only place Chris and Roberta believe Brian may be."

But, the North Port Police Department denied ever asking for Christopher's assistance in the search for his son.

The federal arrest warrant was issued against Laundrie on Sept. 22, but he has not been charged in Petito's death. Laundrie's sister Cassie recently opened up about her brother's disappearance, saying she doesn't know if her parents are involved in any way in the case.

"We are just as upset, frustrated and heartbroken as everyone else," Cassie said.