Dr. Brent Blue said Petito died three to four weeks before her body was found on Sept. 19 in Bridger-Teton National Forest.
While officials initially ruled her death as a homicide, no further details were divulged until Monday.
Blue said authorities had taken DNA samples from Petito's remains, but state law prohibited him from releasing additional information.
Petito went missing during a cross-country van trip with her boyfriend Brian Laundrie, a person of interest in the investigation.
The young couple stopped at various national parks along the way and posted about their "van life" adventures on social media. They started their summer tour in New York on July 22 and made stops in Colorado, Wyoming, and Utah. On Sept. 1, Laundrie returned to his home in Florida without Petito.
Laundrie has since gone missing, and authorities have been searching for him for nearly three weeks. Hundreds of tips on his whereabouts and possible sightings have poured in as the investigation into Petito's death and Laundrie's disappearance have dominated headlines nationally.
Laundrie's parents told police they last saw their son on Sept. 13, two days after Petitio's parents, who live in New York, reported her missing. Laundrie's parents purportedly told authorities their 23-year-old son may have gone to the Carlton Reserve, a 24,000-acre wildlife reserve near their Florida home, to go camping. However, exhaustive searches of the area did not lead to Laundrie.
Laundrie's parents have come under intense scrutiny, but they have denied helping their son evade law enforcement.
Steve Bertolino, an attorney representing the family, said any "speculation" they assisted in Laundrie's disappearance "is just wrong."
"Chris and Roberta Laundrie do not know where Brian is," he said. "They are concerned about Brian and hope the FBI can locate him."
Laundrie's sister, Cassie, said she wanted to see her brother turn himself in. She also called on her parents to come forward if they knew something that could "get us out of this horrible mess."
"I worry about him," she told Good Morning America. "I hope he's OK, but then I'm angry, and I don't know what to think."
An attorney for Petito's family expressed skepticism that Laundrie's family would aid in any search to bring him in for questioning.
"The Laundries did not help us find Gabby, and they're sure not going to help us find Brian," Richard Stafford said. "For Brian, we're asking you to turn yourself in to the FBI or the nearest law enforcement agency."
The Petito-Laundrie mystery became a nationwide obsession as thousands of armchair sleuths combed through clues, dissected details, and debunked theories on what might have happened.
On Aug. 12, the couple was stopped by officers from the Moab Police Department in Utah. Body camera video from the stop includes a conversation between Petito and a police officer as she claims Laundrie hit her.
However, during her first interview with authorities, she said he had not hit her. Instead, she claimed she slapped him repeatedly, and he had pushed her off of him. The couple then separated for the night.
There have been alleged sightings of Laundrie in multiple states, from Florida to as far as the Appalachian Trail.
The sheriffs' offices in Watauga and Avery counties in North Carolina said they had received more than half a dozen tips that Laundrie could be in the area.
The patch of trail has also been the focus of Duane "Dog the Bounty Hunter" Chapman, who formed his own team of searchers for Laundrie.
His daughter Lyssa Chapman tweeted on Oct. 1, "By boat, plane, or train #BrianLaudrie (sic) will be captured and brought to justice."
However, Dog's family dynamics have also made headlines after his other daughter accused him of using Laundrie's disappearance as a publicity stunt to shop around a new reality show.
On Sunday, Dog announced he would take a break from the Laundrie investigation after suffering an ankle injury. He said his "Florida team" would continue to follow leads while he works the case from Colorado.
Laundrie has not been charged in Petito's homicide case. On Sept. 22, the FBI issued an arrest warrant charging Laundrie with unauthorized use of a debit card. The indictment, unsealed on Sept. 23, alleges Laundrie used a Capital One Bank card and someone's personal identification number to make unauthorized withdrawals or charges worth more than $1,000 between Aug. 20 and Sept. 1, the period in which Petito went missing.
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Original Author: Barnini Chakraborty
Original Location: Gabby Petito died by strangulation, coroner reveals