Blogger Gabby Petito embarked on a road trip this July with her fiancé, Brian Laundrie.
A coronor has now confirmed it is the body of the missing girl.
On Sunday, police said a search crew had discovered a body matching the description of Ms Petito at a national park in Wyoming.
Ms Petito, 22, was visiting the Grand Teton National Park with Mr Laundrie, 23, as part of a cross-country camper van road trip.
But after a month of travelling, Mr Laundrie returned home to Florida without Ms Petito.
Mr Laundrie has now gone missing himself.
He is considered a “person of interest” in the case but has not been charged with any crime.
Police raided his parents home and he is on the run currently.
Mr Laundrie and Ms Petito got engaged in July 2020, according to their social media.
The two high school sweethearts documented their nomadic “van life” through national parks in the American West on Instagram and YouTube.
On 12 August, police in the southern Utah town of Moab were called to a possible domestic violence incident involving the couple.
Bodycam footage showed Ms Petito crying and complaining about her mental health to officers. She also said the couple had been arguing more frequently.
A police report of the incident said Mr Laundrie claimed Ms Petito hit him after an argument.
On 19 August, a video was posted to a YouTube channel registered with Ms Petito’s email.
The video showed the couple smiling, kissing and running on beaches. It has been viewed more than 3.2 million times.
Regular social media updates from the couple on Instagram abruptly ended in late August.
Ms Petito video called her mother on 24 August to say she was leaving Utah and heading to the Teton mountain range in Wyoming, according to Rick Stafford, the Petito’s lawyer.
Mr Laundrie and Ms Petito had moved into his parents’ home in North Port, Florida, in 2019.
When Mr Laundrie returned to North Port without his fiancée, he did not contact her family or police.
Mr Laundrie’s attorney Steve Bertolino has said the family “is remaining in the background at this juncture”.
On 20 September, the FBI searched the Laundrie residence for clues.
Authorities had been looking for Mr Laundrie in a 24,000-acre nature reserve near North Port with police dogs and drones as his parents said he may have gone there.
The search resumed on Tuesday after being briefly called off on Monday.
While Mr Bertolino had originally scheduled a news conference on Tuesday, he later cancelled it after speaking to the FBI.
He was quoted by local media as denying that the FBI had advised him to cancel, saying it was not in his “client’s best interest” to go ahead with the event.
The FBI has searched the Florida home of Brian Laundrie, the fiancé of 22-year-old Gabby Petito, a missing woman now believed to be dead.
Agents with a search warrant surrounded the property on Monday. Mr Laundrie’s parents were removed from the home but have since been allowed back inside.
On 1 September, Mr Laundrie, 23, returned home alone after a cross-country road trip with Ms Petito.
On Sunday, remains matching Ms Petito’s description were found in Wyoming.
Police consider Mr Laundrie a “person of interest” in the case but have not charged him with any crime. He declined to speak to police earlier this month, and has since gone missing.
His family has said they last saw him on 14 September.
Video from local media on Monday showed officers and FBI agents approaching the Laundrie home, some with guns drawn, cordoning it off with crime scene tape and placing Mr Laundries’ parents in an unmarked van.
Agents were then seen removing several boxes from the house.
In a tweet, the FBI confirmed it had secured a search warrant in court. “No further details can be provided since this is an active and ongoing investigation,” the agency said after the hours-long search.