MOOSE, Wyo. (AP) — Authorities say a body discovered Sunday in Wyoming is believed to be Gabrielle “Gabby” Petito.

The FBI said the body was found by law enforcement agents who had spent the past two days searching campgrounds.

The cause of death not yet been determined, said FBI Supervisory Special Agent Charles Jones.

“Full forensic identification has not been completed to confirm 100% that we found Gabby, but her family has been notified,” Jones said. “This is an incredibly difficult time for (Petito’s) family and friends.”

An attorney who has been acting as a spokesman for the Petito family could not be reached immediately for comment.

An undeveloped camping area on the east side of Grand Teton bordering national forest land will remain closed until further notice while the investigation continues, Jones said.

Jones said investigators are still seeking information from anyone who may have seen Petito or boyfriend Brian Laundrie around some camping sites located on Grand Teton National Park's eastern boundary, the same site that was the subject of a law enforcement search efforts over the weekend.

Petito, 22, and Laundrie, left in July on a cross-country trek in a converted van to visit national parks in the U.S. West. Police said Laundrie was alone when he drove the van back to his parents’ home in North Port, Fla., on Sept. 1.

Laundrie has been identified as a person of interest in the case. He was last seen Tuesday by family members in Florida.

More than 50 law enforcement officers on Sunday started a second day of searching for Laundrie at the more than 24,000-acre Carlton Reserve in Sarasota County, Fla., a wildlife area with more than 100 miles of trails, as well as campgrounds.

Petito’s family filed a missing persons report Sept. 11 with police in Suffolk County, N.Y.

Petito’s family had been pleading for the Laundrie family to tell them where their son last saw her. Petito and Laundrie were childhood sweethearts who met while growing up on Long Island, N.Y. His parents later moved to North Port, about 35 miles south of Sarasota.

The couple’s trek in the Fort Transit van began in July from Long Island. They intended to reach Oregon by the end of October according to their social media accounts, but Petito vanished after her last known contact with family in late August from Grand Teton National Park, authorities said.

The FBI in Denver said Saturday that agents had been conducting ground surveys at Grand Teton National Park, with help from the National Park Service and local law enforcement agencies, seeking clues to Petito’s disappearance.

FBI agents tweeted that they were focusing on an undeveloped camping area near Spread Creek on the east boundary of the park, which was closed to the public during the surveys. They urged anybody who had been there between Aug. 27 and 30, and had seen Petito, Laundrie or their vehicle, to contact them.