TIMELINE: What happened to Gabby Petito?
The tragic development came after the Teton County Coroner said authorities had responded to a body found at the Teton National Forest in Wyoming, the same general area where law enforcement had been searching for Gabby Petito.
FBI in Denver confirmed the discovery during a press conference Sunday night at the Craig Thomas Discovery and Visitor Center in Grand Teton National Park.
WATCH: FBI update on body found in Wyoming forest
FBI says Body matching description of Gabby Petito found in Grand Teton
They say full forensic identification has not been completed and they do not know the cause of death yet.
"Full forensic identification has not been completed to confirm 100% that we found Gabby, but her family has been notified," FBI Supervisory Special Agent Charles Jones said. "This is an incredibly difficult time for Petito's family and friends."
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.
Aerials near site where remains found in search for Gabby Petito
Aerials near site where remains found in search for Gabby Petito
Petito's father, Joseph, tweeted a heartbreaking message following the discovery, saying "she touched the world."
The Laundrie family attorney released a statement on Sunday night saying, "The news about Gabby Petito is heartbreaking. The Laundrie family prays for Gabby and her family."
The development in the Petito case comes as police in North Port concluded their search for Brian Launderie, who remains missing as of Sunday night.
North Port Police tweeted their condolences, saying they are "heartbroken to learn that Gabby has been found deceased."
Just before the announcement by the FBI, the North Port PD said they had nothing to report after another day searching a vast wildlife reserve for the 23-year-old Laundrie, a person of interest in the disappearance of his girlfriend.
Local and federal law enforcement combed through a massive county park known as the Carlton Reserve, which spans more than 24,000 acres and is located just north of the home which Laundrie and Petito shared with his parents.
Police readied ATVs to be able to comb through as much of the reserve as possible and blocked off all entrances to the public.
Steven Bertolino, the Laundrie family attorney, told ABC News on Sunday that the family picked up the car Brian Laundrie was using on Thursday morning from the reserve after going out on Wednesday to look for their son.
Laundrie left the family home on Tuesday morning with a backpack. Bertolino said that the family went out to the reserve on Wednesday to look for him and spotted a note from the North Port Police Department on the car saying it needed to be removed.
The family left the car overnight "so he could drive back," the attorney said. When Laundrie didn't come home Thursday morning, the family went back to retrieve the car.
WATCH | Chopper hovers over police search for Brian Laundrie at Carlton Reserve
Video: Police search for Brian Laundrie continues in Carlton reserve
The family then called police on Friday to file a missing person report, authorities said on Saturday.
Tips on the case have begun to pour in on social media, like from Miranda Baker, who said in a Tik Tok video that she and her boyfriend picked up Laundrie who was hitchhiking around Teton Park on August 29.
About 45 seconds into the Tik Tok video, Baker says "He offered to pay us like $200 to give him a ride like 10 miles, so that was kind of weird ... without his fiancé."
Former FBI agent, Brad Garrett, on the search for Gabby Petito, Brian Laundrie:
Former FBI agent on the search for Gabby Petito
Petito's family says Laundrie is not missing, but is in hiding.
The Petitos released the following statement through their attorney overnight Saturday:
"All of Gabby's family want the world to know that Brian is not missing, he is hiding. Gabby is missing."
Police shared new photos from the search for Laundrie around the Carlton Reserve area.
Still, police consider Laundrie a missing person.
Speaking to Good Morning America Saturday, North Port Police Public Information Officer Josh Taylor said police were "trying to corroborate everything they've been telling us" in regards to what they've been told by his family.
Taylor said detectives spoke with Chris and Roberta Laundrie in person with their lawyer present over the phone.
"I wouldn't say that it was, you know, a full conversation. Right now their focus was on us helping them find their son," Taylor said.
Taylor said investigators were still working to piece together Brian's trip from western states to their home in Florida.
"Certainly that truck did not drive from, you know, potentially, you know, the mountain west to here on one tank of gas so we know there were stops along the way. If people saw anything as far as those movements, we're piecing that together, some parts of the timeline we've solidified. We know her mother talked to her, saw her on facetime on the 25th of August," Taylor said.
Watch the full GMA interview with Josh Taylor:
Police officer discusses meeting with Brian Laundrie's parents
"We are happy they called the police in and they want to cooperate, but until...I'm not going to speculate, I don't know what to believe," said Petito's stepfather, Jim Schmidt.
A spokesperson for the department appeared on CNN later Friday night and said the department does have more details but they cannot be released just yet.
"I think that will come out here, very shortly, we just want to get our, our ducks in a row a little bit," the spokesperson said. "This has been a very quickly developing situation here in just the last hour really for the most part. So we're working through that. We want to make sure that we are accurate in everything that we're saying."
Petito, a 22-year-old woman originally from Long Island, disappeared on a cross-country road trip with Laundrie.
The Florida couple were traveling to Oregon when Petito stopped communicating with her family somewhere in Wyoming in late August.
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Laundrie, who has been named a person of interest by police in North Port, Florida -- returned to their Gulf Coast home in Petito's 2012 white Ford Transit van on September 1, 10 days before Petito was reported missing by her family in Blue Point.
Police in North Port held a news conference Thursday during which Petito's father begged for her safe return and for Laundrie to speak up and stop hindering the investigation.
"What I need from everybody is help," Joseph Petito said. "That goal is to bring Gabby home safely. I'm asking for help from everyone here. I'm asking for help from everyone at home. I'm asking for help from the parents of Brian, and I'm asking for help from the family members and friends of the Laundrie family as well."
MORE: Police body cam video shows Gabby Petito, boyfriend after 911 call
Police release body cam video of intereaction with Petito, Laundrie
Petito's mother, Nichole Schmidt, said the last video chat she had with her daughter was August 24 or 25, though they exchanged text messages for a few days following.
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She has since said she is unsure if it was her daughter actually sending those texts.
"We don't eat, we don't sleep, we're just actively looking for her," she said.
The engaged couple had been documenting their trip on YouTube, and they were set to arrive in Portland in October.
"We were excited for them," Schmidt said. "I believe she's in danger because she's not in touch with us. She could be alone somewhere. She could be stranded somewhere in the wilderness and she needs help."
Petito is described as a white female, approximately 5-foot-5 and 110 pounds.
She has blonde hair, blue eyes, and several tattoos, including one on her finger and one on her forearm that reads "Let it be."
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