The FBI says a county coroner has confirmed that human remains found in remote northern Wyoming along the border of Grand Teton national park are those of 22-year-old Gabby Petito, who disappeared while on a cross-country road trip with a fiance who is now being sought by authorities in Florida. The Teton county coroner, Brent Blue, determined her manner of death was homicide, but did not disclose a cause of death pending final autopsy results, officials said Tuesday. Petito’s body was found Sunday near an undeveloped camping area that’s surrounded by woodlands and brush, located about 30 miles (48km) northeast of Jackson, Wyoming. The FBI also requested for anyone with information about Brian Laundrie’s role in Petito’s death to contact the agency. Investigators have called Laundrie, 23, a “person of interest”. His parents told FBI agents they last saw him a week ago, when he told them he was planning to hike alone in the 24,000-acre Carlton Reserve wilderness area, near North Port, Florida. North Port police said Tuesday morning that investigators have returned to the reserve to look for Laundrie. Investigators searched the 24,000-acre (9,700-hectare) reserve over the weekend without success. Authorities are using helicopters, drones, dogs and officers in all-terrain vehicles in their search for Laundrie. About 75% of the search area is underwater. Petito and Laundrie were childhood sweethearts who met while growing up on New York’s Long Island. His parents later moved to North Port, just south of Sarasota. Petito and Laundrie left her home state of New York in late June or early July, heading west in her white van to visit national parks and document the trip on social media. Laundrie returned home to North Port alone in the van on 1 September. Ten days later members of Petito’s family reported her missing. Before disappearing, Laundrie refused to speak with investigators and retained a lawyer. Witnesses last saw Petito on 24 August as she left a hotel in Salt Lake City. She posted her final photo on social media the next day. Her family believes she was headed to Grand Teton national park in Wyoming when they last heard from her. A body was discovered on the edge of that park, in a remote area less than 1,000ft from where a pair of travel bloggers filmed the white van parked on a dirt road near Spread Creek on the evening of 27 August. A man who saw Petito and Laundrie fighting in Moab, Utah, on 12 August called 911 to report a domestic violence incident, according to a recording of the call obtained from the Grand county sheriff’s office. The man said he saw Laundrie slap Petito while walking through the town and proceeded to hit her before the two got in their van and drove off. Video released by the Moab police showed that an officer pulled the couple’s van over on the same day after it was seen speeding and hitting a curb near Arches national park. The body-camera footage showed Petito crying. Moab police separated the couple for the night, with Laundrie checking into a motel and Petito remaining with the van.