Gabby Petito's Friends React to Her Cause of Death: 'She Must Have Been So Scared'

Gabby Petito's death was ruled a homicide last month following an autopsy by the Teton County Coroner's Office, but further findings were not revealed until Tuesday

Friends of Gabby Petito's are speaking out about Tuesday's announcement that the 22-year-old died of strangulation.

"It makes me sick to my stomach," friend Alyssa Chen tells PEOPLE. "I wonder what was going through her mind, knowing she was probably about to die. She must have been so scared."

Petito and her fiancé, Brian Laundrie, were on a cross-country trip when she vanished in August. While she had been blogging upbeat stories and videos of her so-called "van life," police reports and witness statements allege that the trip was filled with arguments and possible domestic abuse.

Gabby Petito. Gabby Petito Instagram

Brian Laundrie, Gabby Petito. North Port Police Department/Facebook

On August 12 — about two weeks before Petito vanished — police outside Moab, Utah, were called after a witness said that Laundrie had hit Petito during an argument.

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Another eyewitness, who provided a written statement, told police he saw the couple in the middle of "some sort of dispute" and that "something definitely didn't seem right." That witness also said it appeared Laundrie was trying to lock Petito out of the van and take her phone.

Moab Police responded to the scene. They classified the incident as "disorderly conduct" rather than domestic violence, and determined Petito, who admitted to striking Laundrie, was the aggressor. They had the couple spend the night apart so they could cool down.

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Three weeks later, Petito vanished, but wasn't reported missing until Sept. 11 — 10 days after Laundrie allegedly arrived back in Florida. On Sept. 15, he was officially named a person of interest in his fiancée's disappearance.

Gabby Petito, Brian Laundrie. Find Gabby/Facebook

Days later, her body was found in Grand Teton National Park.

Laundrie is now missing, and has not been located despite exhaustive searches in a Florida wildlife preserve, where he is believed to have gone hiking on the day that he vanished.

Now, friends of the couple are expressing anger towards Laundrie.

"If Brian strangled her, I hope he burns in hell," says friend Ben Matula, who was friends with the couple. "That's all I have to say."

Adds Chen: "Whoever did this, whether it's Brian or someone else, needs to pay for what they did. She didn't deserve to die that way."