The circumstances which led to Gabby Petito’s death have been laid bare as the search for her boyfriend enters its third week.

The horrific circumstances around Gabby Petito’s murder have been released in “unexpected” detail by a Wyoming coroner, including exactly when the 22-year-old took her last breath.

After a desperate ground and air search in Wyoming, USA, the FBI discovered Ms Petito’s remains at a campground in the Bridger-Teton National Forest on September 19. Teton County coroner Dr Brent Blue identified the remains in the days after the discovery, and quickly ruled Ms Petito’s death a homicide in his preliminary autopsy report.

Dr Blue has today released more details about her death, a decision some commentators labelled “unexpected”. The coroner revealed Ms Petito died from “strangulation” and the “manner is homicide.”

“After a detailed investigation by our forensic pathologists, our anthropologists and local law enforcements, the Teton County Coroner’s Office filed the following verdict in the death of Gabrielle Petito,” Dr Blue said.

“We hereby find the cause and manner of death to be … the cause death by strangulation, and the manner is homicide.”

Dr Blue said no other information about the autopsy will be released, however they are estimating Ms Petito died three to four weeks before the body was found in an outdoor environment.

Despite speculation Ms Petito was pregnant, Dr Blue confirmed that not to be true, and stressed that information about a potential suspect would have to come from law enforcement.

During the final autopsy announcement, Brian Laundrie’s family lawyer Steven Bertolino released a statement.

“Gabby Petito’s death at such a young age is a tragedy,” Bertolino said.

“While Brian Laundrie is currently charged with the unauthorised 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.”

Ms Petito’s parents, Joseph Petito and Nichole Schmidt, reported their daughter missing eight days before her remains were discovered by police. The travel blogger was travelling cross-country in a Ford transit van with her fiance, Brian Laundrie, when she went missing.

Mr Laundrie, returned home to North Port, Florida, on September 1 in the van without Petito, who owned the vehicle.

Dr Blue said the length of time it took to release the final autopsy was due to being very exact” in their examination of Petito’s body.

“We were waiting for various specialists to come in and we were waiting on toxicology to be returned,” he said, adding “it was a matter of having everything right”.

Dr Blue confirmed DNA samples were taken from Ms Petito by police.

The 23-year-old is now a person of interest in the case, and his whereabouts have been unknown for weeks prompting a massive land, water and air search around Carlton reserve near North Port, Florida. His parents, Roberta and Chris, claim their son went for a hike in the reserve on either September 13 or September 14 but failed to return, forcing the pair to report him missing to local police on September 17.

On September 23, the FBI issued an arrest warrant for Mr Laundrie, accusing him of bank card fraud. Authorities alleged at the time that he used an unidentified person’s Capital One card and the personal identification number to charge or withdraw over $US1000 between August 30 and September 1, during which time Ms Petito was still missing.

Ms Petito’s parents have issued multiple pleas for Mr Laundrie to turn himself in and assist police with inquiries into how the travel blogger died.

Speaking with Dr Phil earlier this month, Mrs Schmidt begged Laundrie to come forward because they “want to know the truth.”

Ms Petito’s stepmother Tara, added: “If you truly loved her, you should turn yourself in.”

Ms Petito’s stepfather Jim said Laundrie was only “making it worse” for himself — and the entire family.

“Let us have some closure,” he begged.

“Let us bring an end to this tragic period, and just be able to move on and remember Gabby and all the wonderful memories we had with her, and not looking at a TV screen everyday wondering if he was going to be found. Just turn yourself in.”

The autopsy results come as neighbours continue to vandalise the home of the Laundries in North Port, Florida.

Over the weekend, a group of neighbours decided to make a statement to the Laundrie family by putting a sign in front of their home.

The Laundries have been the focus of negative attention from across the US — and even the world — after their son went missing during the investigation into the disappearance and death of his fiancee.

The women, who claimed they lived across the street from the Laundrie home, hammered a large image into the of Gabby that read, “Remember me? Gabby Petito. Roberta & Chris, I once lived with you!”

Mr Laundrie has recently joined in the search for his son, with his lawyer Steven Bertolino confirming he was assisting authorities at Carlton Reserve,

“Chris Laundrie was asked to assist law enforcement in their search for Brian at the preserve today,” Mr. Bertolino said.

“Since the preserve has been closed to the public, Chris has not been able to look for Brian in the only place Chris and [wife] Roberta believe Brian may be.”