Petito was reported missing by her family in September after she embarked on a cross-country trip with Brian Laundrie, her fiancé.
Laundrie, who returned to the couple's North Port, Florida, home in early September without Petito, left the home roughly two weeks later and disappeared, sparking a weekslong search for him in a vast Florida nature reserve.
Just days into the search for Laundrie, authorities on the other side of the country discovered Petito's remains in Wyoming and a coroner ruled her cause of death to be strangulation.
After local and federal authorities combed through the 25,000-acre reserve in Florida for weeks, investigators announced they found Laundrie's remains and a medical examiner ruled he died by suicide. Nearby, authorities found a notebook in which Laundrie claimed responsibility for Petito's death, the FBI says.
Here's how the case unfolded.
Petito and Laundrie embark on a cross-country trip, according to North Port Police Chief Todd Garrison, who refers to Laundrie as Petito's fiancé.
They planned to travel in Petito's white Ford van to the West Coast and visit state and national parks across the western United States, Garrison says at a news briefing.
She had been excited to share her journey with her family and others on social media, he says.
"She maintained regular contact with her family members during her travels; however, that communication abruptly stopped around the end of August," the police chief adds.
Moab, Utah, police have an encounter with the couple on August 12, where officers describe them as having "engaged in some sort of altercation."
Although the two are described as getting into a physical fight following an argument, "both the male and female reported they are in love and engaged to be married and desperately didn't wish to see anyone charged with a crime," a report from officer Eric Pratt says.
At officers' suggestion, the couple separated for the night, according to the report, which describes Petito as "confused and emotional."
"After evaluating the totality of the circumstances, I do not believe the situation escalated to the level of a domestic assault as much as that of a mental health crisis," Officer Daniel Robbins writes in the report. No charges are filed.
The couple each had their own cell phones in case of emergency, the report adds.
In a 911 audio recording from that day provided by the Grand County Sheriff's Office, a caller tells dispatch he wanted to report a domestic dispute and described a white van with a Florida license plate.
The caller said as they were driving by, "the gentleman was slapping the girl."
"Then we stopped," the caller added. "They ran up and down the sidewalk. He proceeded to hit her, hopped in the car and they drove off."
Laundrie flew to Tampa, Florida, from Salt Lake City on August 17, according to Laundrie family attorney Steven Bertolino.
Laundrie "flew home to obtain some items and empty and close the storage unit to save money as they contemplated extending the road trip," Bertolino told CNN.
On August 23, Laundrie returned to Salt Lake City to rejoin Petito, the attorney said, adding, "To my knowledge Brian and Gabby paid for the flights as they were sharing expenses.
On August 27, a Louisiana couple 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 August 27 but declined to give her name or describe what happened, and said the restaurant did not have surveillance video of the incident.
Petito's family told police they were last in contact with her during the last week of August, North Port police say. Before that last communication, Petito is believed to have been in Grand Teton National Park in Wyoming, police say.
In a news conference in September, Petito family attorney Richard Stafford says the family's last communication with Petito was August 30, but they do not believe the message they received was from her.
Stafford shares a timeline of events on September 17, as the family knows it:
Also in September, a woman publicly claimed she and her boyfriend gave Laundrie a ride on August 29 in Wyoming -- and Laundrie claimed he'd been camping by himself for multiple days while Petito was at their van working on social media posts.
In a series of videos posted on TikTok, Miranda Baker said she and her boyfriend picked up Laundrie that evening while he was hitchhiking in Colter Bay, Wyoming. Laundrie told them he had been camping at a site outside the Grand Teton National Park, near the Snake River, she said.
Once Laundrie found out Baker and her boyfriend were going to Jackson Hole instead of Jackson, he got agitated, asked that the vehicle stop, and got out near the Jackson Dam, according to Baker.
Baker said she spoke to law enforcement about the interaction. North Port police confirmed to CNN Baker spoke with the department before posting the videos on TikTok.
"Her account is plausible, it appears," North Port police spokesperson Josh Taylor said. CNN has not been able to independently verify Baker's claims.
Additionally, Norma Jean Jalovec, a seasonal Wyoming resident, told CNN she picked up Laundrie not far from Jackson Lake Dam on August 29 and gave him a ride to the Spread Creek dispersed camping area, where Petito's remains were later found.
According to Jalovec, Laundrie told her he and his fiancée had a travel blog, she was in their van at the camping area working on the blog, and he had been hiking along the Snake River embankment for a few days. Jalovec said she later provided the FBI with that information.
Jalovec said when they arrived at Spread Creek, she dropped Laundrie off before the gate at the entrance of the camping area. She said she offered once or twice to take him farther, but he was insistent that he be dropped off at the entrance. Laundrie then offered her gas money, but she declined, she said.
Jalovec said she picked him up around 6:15 p.m., which was just a few minutes after Baker had said Laundrie had departed her vehicle.
Laundrie returns to the couple's North Port home, where his parents also live, on September 1, according to police.
According to an affidavit attached to a search warrant request, a license plate reader shows the vehicle exited Interstate 75 into North Port at 10:26 a.m. ET.
The white vehicle Petito and Laundrie had been traveling in was later recovered by police at the home. It was processed and "there was some material in there" authorities will be going through, Taylor, the police spokesperson, says at a news briefing.
The Laundrie family goes to a campground about 75 miles away from their home in early September, according to county officials.
Roberta Laundrie, Brian Laundrie's mother, was checked in at a waterfront site at the Fort De Soto Campground from September 6 through September 8, according to a Pinellas County Parks campground check-in report provided to CNN.
The Laundries were at the campground from September 6 to September 7 and left altogether, Bertolino later told CNN.
After not being able to get in touch with her, Petito's family -- who lives in New York -- reports her missing to police in Suffolk County, New York.
North Port authorities go to Laundrie's home that night and ask to speak to him and his family, but "we were essentially handed the information for their attorney," Taylor, the police spokesperson, says.
"That is the extent of our conversation with them," Taylor says.
In a letter read by the Petito family attorney at a news briefing held by police, the missing woman's family begs for Laundrie's family to help in the investigation.
"Please, if you or your family have any decency left, please, tell us where Gabby is located," Stafford says. "Tell us if we are even looking in the right place. All we want is for Gabby to come home. Please help us make that happen."
He says Petito's family reached out to Laundrie's family earlier in the month for information on Petito's whereabouts, but his family refused to answer.
"We haven't been able to sleep or eat, and our lives are falling apart," the Petito family's letter adds.
After several days of both Petito's family and police pleading with Laundrie's family to cooperate in the investigation, Laundrie's family requests the police come to their home, where they share they haven't seen Brian since September 14, according to Taylor, the police spokesperson.
"We've been trying all week to talk to his family, to talk to Brian, and now they've called us here on Friday, we've gone to the home, and they're saying now they have not seen their son," Taylor tells CNN's Chris Cuomo. "It is another twist in this story."
Bertolino, the Laundrie family attorney, tells CNN "the whereabouts of Brian Laundrie are currently unknown. The FBI is currently at the Laundrie residence removing property to assist in locating Brian. As of now the FBI is now looking for both Gabby and Brian."
Local and federal authorities kick off a search for the 23-year-old man.
In October, the Laundrie family attorney told CNN that upon further communication with the FBI, the parents now believe that Brian left to hike on September 13, not September 14.
"The Laundries were basing the date Brian left on their recollection of certain events," Bertolino, the attorney, said on October 6.
North Port police say authorities are conducting a search for Laundrie at the Carlton Reserve, a nature area with more than 80 miles of hiking trails in Venice, Florida.
Roughly 50 law enforcement officers from five local agencies and the FBI are searching for Laundrie, Taylor, the police spokesperson, says at a news conference, adding Laundrie has an "enormous amount of pressure" on him to provide answers to what's going on.
Meanwhile, the FBI announces the agency and its partners are also conducting ground surveys in Grand Teton National Park relevant to Petito's disappearance.
The national park is where Petito is believed to have been before her last communication with her family, police have previously said.
Human remains discovered in Teton County are "consistent with the description of" Petito, FBI officials say in a news conference.
"Full forensic identification has not been completed to confirm 100% that we found Gabby, but her family has been notified of this discovery," says Charles Jones, FBI Denver's supervisory senior resident agent in Wyoming.
The parents of Brian Laundrie are questioned at their home by the FBI.
Christopher and Roberta Laundrie are escorted from their home and return after federal agents executed a search warrant, according to Taylor, the North Port police spokesperson. Authorities search the home for hours.
Police say they have exhausted search avenues at the nature reserve and the search area has shifted.
The Teton County coroner confirms the human remains found in the Bridger-Teton National Forest are those of Petito, according to the FBI.
"The cause of death remains pending final autopsy results," the FBI says.
While authorities continue their search for Laundrie at the Carlton Reserve, the FBI announces the US District Court of Wyoming issued a federal arrest warrant for him.
The warrant was issued pursuant to a federal grand jury indictment for the "use of unauthorized devices" related to Laundrie's activities after Petito's death, the FBI says.
"While this warrant allows law enforcement to arrest Mr. Laundrie, the FBI and our partners across the country continue to investigate the facts and circumstances of Ms. Petito's homicide," Special Agent in Charge Michael Schneider says in a statement. "We urge individuals with knowledge of Mr. Laundrie's role in this matter or his current whereabouts to contact the FBI."
Laundrie is suspected of using a debit card and PIN for accounts that do not belong to him for charges of more than $1,000 sometime between August 30 and September 1, according to the indictment.
After a detailed investigation by forensic pathologists, anthropologists and local law enforcement, with assistance from the FBI, Petito's cause of death was determined to be strangulation, Teton County Coroner Brent Blue announces.
By Wyoming law, no other information apart from manner and cause of death will be released about the autopsy, Blue says at a virtual news conference.
The coroner says that Petito's body was outside in the wilderness for about three to four weeks before being found.
Laundrie remains missing. Authorities have not explicitly connected him to Petito's death.
Weeks into the search for Laundrie at Florida's Carlton Reserve, investigators found what appear to be human remains along with personal items including a backpack and notebook belonging to Laundrie, FBI Tampa Division Special Agent in Charge Michael McPherson announced in an evening news conference on October 20.
The items were found in an area that had been underwater until recently, McPherson said.
"I know you have a lot of questions, but we don't have all the answers yet," McPherson added.
Earlier in the day, the Laundrie family attorney said "some articles" belonging to Laundrie were found off a trail he frequented at Myakkahatchee Creek Environmental Park, a site connected to the Carlton Reserve.
Laundrie's parents informed the FBI and North Port police the night prior that they intended to come to the park to search for Laundrie, Bertolino says.
Law enforcement meets them there and after a "brief search" the family and law enforcement found articles belonging to him, the attorney adds.
The Sarasota County medical examiner and a cadaver dog were called to the Carlton Reserve area, CNN confirmed.
In a tweet on the same day, the FBI says "items of interest" were found in connection with the search. "An #FBI Evidence Response team is processing the scene," the FBI said. "The reserve is closed to the public and no further details are available at this time."
The FBI announces that a comparison of dental records confirmed the human remains found a day earlier are those of Brian Laundrie.
Earlier Thursday, Taylor, the police spokesperson, tells CNN what authorities found were "skeletal remains" as well as clothing believed to belong to Laundrie.
"It's consistent with what he was believed to be wearing," Taylor says.
Taylor indicates the items had been out there for some time.
A source with knowledge of the investigation also tells CNN's Randi Kaye that the notebook discovered among other belongings is "possibly salvageable."
The District Twelve medical examiner's office in Florida says its investigation into Laundrie's death determined he died by suicide from a gunshot wound to the head.
Announcing the case is coming to a close, the FBI releases a timeline outlining the Petito case.
In a January 21, 2022, news release, the agency says after reviewing the contents of the notebook found near Laundrie's remains, they found "written statements by Mr. Laundrie claiming responsibility for Ms. Petito's death."
The FBI also confirms it was Petito's debit card Laundrie used without authorization between August 30 and September 1 on his drive back to Florida from Wyoming and several messages exchanged between Laundrie's phone and Petito's phone after her death were likely Laundrie's attempt "to deceive law enforcement by giving the impression that Ms. Petito was still alive."
The agency says they met with Petito's family and the investigation "will be closed in the near future.
"All logical investigative steps have been concluded in this case," Schneider, the special agent in charge, said in a statement. "The investigation did not identify any other individuals other than Brian Laundrie directly involved in the tragic death of Gabby Petito."