The Long Island woman's body was discovered on Sept. 19 at the Spread Creek Dispersed Camping Area in Bridger-Teton National Forest, and Teton County Coroner Dr. Brent Blue had previously ruled her death a homicide.
But the 22-year-old's official cause of death wasn't disclosed until Tuesday, though Blue cited state law in limiting the amount of information he could share.
In a memo dated Oct. 5 and filed on Tuesday, Blue listed Petito's manner of death as homicide and the cause as, "Death by manual strangulation/throttling."
"Our initial determination is the body was in the wilderness for three to four weeks" before she was found, Blue told reporters, which would place her time of death in mid to late August.
Throughout his meeting with reporters, Blue sidestepped questions about who could have been responsible for the woman’s death. But the coroner did appear to imply that Petito was a victim of domestic violence.
“This is only one of many deaths around the country of people who are involved in domestic violence and it’s unfortunate that these other deaths do not get as much coverage as this one," Blue said.
Steven Bertolino, an attorney for Laundrie's family, reiterated that Brian Laundrie is not a suspect in Petito's disappearance or death.
“Gabby Petito’s death at such a young age is a tragedy," Bertolino, said in a statement on Tuesday afternoon.
"While Brian Laundrie is currently charged with the unauthorized use of a debit card belonging to Gabby, Brian is only considered a person of interest in relation to Gabby Petito’s demise. At this time Brian is still missing, and when he is located we will address the pending fraud charge against him."
Petito and Laundrie were on a cross-country road trip, chronicling their travels on social media, before he returned to his parents' home in North Port, Florida, arriving there Sept. 1 without his fiancée, police said.
The woman's family reported her missing Sept. 11, and Laundrie himself soon vanished.
Laundrie’s family told investigators he had gone hiking Sept. 14 in the Carlton Reserve in Florida and never returned. Law enforcement searched the 25,000-acre wildlife refuge multiple times looking for him.
There have been numerous reported sightings of Laundrie up and down the East Coast since.
Police have thus far only called Laundrie a "person of interest" in their investigation into Petito's disappearance, but an arrest warrant was issued for him after authorities said he used her debit card without permission
Also last month, the Grand County Sheriff's Office in Utah released 911 audio from a witness who said he saw a man slap a woman and then saw a white Ford Transit van bearing a Florida license plate drive away.
The 911 call led Moab police to stop the van — driven by Laundrie, with Petito as a passenger — on Aug. 12.
The incident appeared to be a mental and emotional "break," police said, writing that Petito had slapped Laundrie. They forced the couple to separate for the night to avoid a case of domestic assault against Petito.