For the past year, the young woman regularly posted pictures with Laundrie on her Instagram account, sharing last May she couldn't wait to start "traveling the world" with him and several weeks later, in July 2020, announcing he had asked her to marry him.
"I said yes!" Petito had written in an Instagram caption. "Everyday is such a dream with you."
She documented their trip this summer on social media, posting pictures of herself smiling in Kansas' Monument Rocks, posing on the Great Sand Dunes in Colorado and taking in the views of Utah's Bryce Canyon National Park.
But when the camera turned off, a different reality was unfolding. The trip seemed to be straining the relationship and the two were seen arguing by passersby -- at one point so intensely, at least one person called authorities to report it.
Petito called her mom regularly, and those conversations appeared to reveal there was "more and more tension" in Petito's relationship, according to a police affidavit for a search warrant of an external hard drive found in the couple's van.
"She would go off the grid, you know, while she was out there, doing her van-life stuff, exploring these different areas," Jim Schmidt, Petito's stepfather had said when she was missing. "It wasn't uncommon for her to go off for a few days at a time but she'd always make her way back to someplace where she could get on to a Wi-Fi connection, upload to her Instagram, make phone calls, FaceTime to come home."
The FBI announced on September 19 authorities had found human remains "consistent with the description of" Petito. The remains were later confirmed to be those of Petito. The FBI said the initial determination for Petito's manner of death is homicide.
New, slowly emerging details help paint a picture of what the days before Petito's death may have looked like.
The two were stopped by police
On August 12, nearly three weeks before Laundrie arrived back in Florida at the home he shared with Petito and his parents, someone drove by a couple with a white van with a Florida license plate and called 911 to report they saw "the gentleman was slapping the girl."
"Then we stopped," the caller told dispatchers, according to a 911 audio recording from that day that was provided by the Grand County Sheriff's Office. "They ran up and down the sidewalk. He proceeded to hit her, hopped in the car and they drove off."
A Moab, Utah, police officer who spotted the van later wrote in a police report he saw Petito sitting in the passenger seat and "crying uncontrollably."
In bodycam footage from the Moab Police Department that was obtained by CNN, an officer is heard asking the young woman, who was visibly shaken, to step out of the van and sit inside his vehicle in hopes of helping her calm down. Petito said the two had been fighting that morning and going through "some personal issues."
"I have OCD and sometimes I get really frustrated," Petito said, adding later, "He wouldn't let me in the car before."
When the officer asked why, the young woman responded, "He told me I needed to calm down, but I'm perfectly calm."
"At no point in my investigation did Gabrielle stop crying, breathing heavily, or compose a sentence without needing to wipe away tears, wipe her nose or rub her knees with her hands," officer Daniel Scott Robbins wrote in the report.
Robbins wrote he did not believe the "situation escalated to the level of a domestic assault as much as that of a mental health crisis." He suggested the two separate for the night, to which Petito and Laundrie agreed.
"I was able to contact Safe Haven and get Brian a hotel room for the night," Robbins wrote. "I instructed both Brian and Gabrielle to take advantage of this time apart to relax their emotions ... also asked them to avoid contacting each other until the next morning if at all possible."
Petito kept the van while Robbins took Laundrie to the hotel, the officer wrote, adding that they both had their cell phones on them in case of emergency.
A witness on site wrote in a sworn statement the two were "talking aggressively at each other and something seemed off."
Chris, the witness -- whose last name was redacted in the document provided to CNN by Moab police -- said it appeared the two were arguing over control of Petito's phone, and said he saw the young woman at one point "punching (Laundrie) in the arm and/or face and trying to get into the van."
"Why do you have to be so mean," Chris wrote he heard Petito say to Laundrie, although Chris added that he couldn't be sure whether the comment was meant to be taken seriously.
A National Park Service ranger who also responded to the call spent about an hour and a half with Petito and warned her that her relationship with Laundrie had markings of a "toxic" one, Melissa Hulls, the ranger, told the Deseret News of Utah.
"I was imploring with her to reevaluate the relationship, asking her if she was happy in the relationship with him, and basically saying this was an opportunity for her to find another path, to make a change in her life," Hulls told the Deseret News.
A post on Petito's Instagram account on the same day was tagged at the Arches National Park near Moab. A caption on that post says the couple had spent some time taking photos and "drawing and enjoying the nature," near the arches.
Petito FaceTimed with her mom
Petito called and texted her mother regularly throughout the trip, according to the search warrant which described an apparent growing tension between Petito and Laundrie.
On August 24, Petito FaceTimed with her mother and told her she was leaving Utah and heading to the Teton mountain range, in Wyoming, Petito family attorney Richard Stafford has said.
A day later, the mother and daughter texted again, during which time her family believed Petito was in the Tetons, Stafford said previously.
'Commotion' inside a restaurant
On August 27, five days before Laundrie arrived in Florida, a Louisiana couple who was vacationing in Jackson, Wyoming, said they saw Petito and Laundrie involved in a "commotion" as they were leaving The Merry Piglets Tex-Mex restaurant.
Nina Angelo, who was at the restaurant with her boyfriend, said Petito was in tears and Laundrie was visibly angry, going in and out of the restaurant several times and showing anger toward the staff around the hostess stand. A restaurant manager told CNN she saw "an incident" at the restaurant on August 27 but declined to give her name or describe what happened and said the restaurant did not have surveillance video of the incident.
On the same day, Petito's mother received what she described as an "odd text" from her daughter, the search warrant said, and was concerned something was wrong.
"Can you help Stan, I just keep getting his voicemails and missed calls," the message read, according to the search warrant. Stan was a reference to Petito's grandfather, who her mother said Petito never referred to that way, according to the warrant.
Also on August 27, a pair of vloggers' GoPro video captured Petito's van in the Spread Creek Dispersed Camping Area, where Petito's body was later found, between 6 to 6:30 p.m. local time.
The vloggers, Kyle and Jenn Bethune, said when they saw the van's Florida license plates they considered stopping to say hello, since they were from Florida as well, but Jenn Bethune said nobody seemed to be around the vehicle.
"We figured maybe they were out hiking or they were just chilling inside," Kyle Bethune added. "There (were) no doors open."
The FBI has asked for information from anyone who was in the camping area between August 27 and August 30, who may have had contact with the couple or seen the vehicle.
According to the timeline Stafford previously provided, the last text from Petito came on August 30, but her family doubted it was her who wrote the message.
"No service in Yosemite," that message read, according to Stafford.
Where Petito was found
On September 19, officials announced the discovery of remains in the Spread Creek Dispersed Camping Area in the Bridger-Teton National Forest. A coroner later confirmed Petito's identity.
The restaurant where authorities have said Petito was last seen is about 25 miles from Spread Creek.
A federal arrest warrant issued last week for Laundrie for the use of unauthorized access devices "in the District of Wyoming and elsewhere" alleges that sometime between August 30 and September 1, Laundrie is suspected of using a debit card and PIN number for accounts that did not belong to him for charges of more than $1,000.
An attorney for Laundrie's family said Thursday the warrant is related "to activities occurring after the death of Gabby Petito and not related to her actual demise."
"The FBI is focusing on locating Brian and when that occurs the specifics of the charges covered under the indictment will be addressed in the proper forum," Attorney Steve Bertolino said.
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