The fiance of the 22-year-old “van life” blogger, whose death has been ruled a homicide, Mr Laundrie was travelling with Ms Petito on a cross-country road trip from New York to Oregon when she went missing in late August.
Mr Laundrie returned to his family’s home in Florida alone on 1 September in the white Ford transit van the couple had been living in and ultimately disappeared himself on 13 September, having apparently told his family he was going for a hike in the nearby Carlton Reserve, a 25,000-acre wilderness.
Days later, when Mr Laundrie’s parents reported his disappearance, a major manhunt was launched, which remains underway amid a flurry of international media interest.
The FBI announced its charge against Mr Laundrie on 23 September for alleged “use of unauthorised access devices”, along with an arrest warrant.
Watch: Chris Laundrie trims grass around Gabby Petito makeshift memorial set up on front lawn
Here’s everything we know about the missing man so far:
Authorities had labelled Mr Laundrie a “person of interest” in Ms Petito’s disappearance as he was the last person known to have been seen with her before she went missing.
The grand jury indictment against Mr Laundrie is not related to her death, however. Instead it concerns money he allegedly withdrew that “affected interstate commerce”. Specifically, Mr Laundrie is accused of fraudulently using someone else’s debit card from 30 August to 1 September, spending or withdrawing $1,000 or more.
After Ms Petito was reported missing, Mr Laundrie’s lawyer, Steve Bertolino, released a statement saying his client would not be speaking to authorities “on the advice of counsel”.
North Port Police, who said Mr Laundrie’s lack of cooperation was “hindering the investigation”, tweeted a direct plea to the lawyer, asking for help.
Mr Laundrie did not speak to police and instead went missing. He has not been seen since 13 September, despite a number of reported sightings that proved to be red herrings.
While the warrant allows for his arrest, the facts and circumstances of Ms Petito’s death are still being investigated.
The Petito family - along with lawyer Richard Stafford - appeared on Dr Phil in early October, during which the attorney claimed Mr Laundrie stole Ms Petito’s debit card and ran from Wyoming.
Ms Petito’s father told the TV psychologist that he hopes Mr Laundrie will “see the inside of a jail cell” for the rest of his life.
Where is Brian Laundrie believed to be?
The search for Mr Laundrie is largely focused on the Carlton Reserve in Florida, which is close to the Laundrie’s family home in North Port.
His parents say he headed to the Myakkahatchee Creek Environmental Park, which connects with the reserve, for a hike on 13 September (they originally gave the date of his disappearance a day later but subsequently revised their statement). Mr Laundrie is said to have departed carrying only a backpack and is known to have driven there in a silver Mustang, which the family has since collected.
While authorities scaled back the search at one point, they later returned to the area with divers to continue hunting for traces of Mr Laundrie among the park’s alligator-infested swamplands.
Following a tip from reality television celebrity Dog the Bounty Hunter, Mr Laundrie’s parents confirm they went camping with their son between 6 and 8 of September at the Fort De Soto Park in Florida’s Pinellas County, days before Ms Petito was reported missing by her mother, Nicole Schmidt. A couple who was camping next to the Laundries may have even captured a photo of Mr Laundrie walking by in the image’s background.
After Mr Laundrie went missing and became the subject of a nationwide search, several people reported seeing him around the time of the couple’s road trip.
One couple said they got into a minor argument with him while he was allegedly drinking at a bar and “angry at the world” in West Yellowstone.
Another woman started a TikTok to share her bizarre story of picking up a hitchhiker who resembled Mr Laundrie and said his name was Brian. She described the man as acting strange and eventually “freaking out” when he realised he was heading south.
There have also been a slew of reported sightings since his disappearance, placing Mr Laundrie in Canada, Mexico, and at least four states. One Appalachian Trial hiker said he was “99.99 per cent sure” he met Mr Laundrie while he was hiking. He reported his encounter to the FBI.
As of early October Mr Laundrie is still on the run, and - despite the numerous reported sightings - no trace of him has been found.
Is he a survivalist?
Mr Laundrie told friends and co-workers that he was skilled in outdoor survival, allegedly boasting to a colleague that he had lived in a forest for weeks on just snacks.
He also reportedly told a friend of Ms Petito’s that he spent three months hiking alone in the Appalachians. However, his sister, Cassie Laundrie, claimed he was only a “mediocre” survivalist.
Experts have said the swampy region they are searching for him in is particularly unforgiving due to the prevalence of dangerous wild animals and the likelihood of suffering dehydration in the humidity.
Watch: Coroner says Gabby Petito's cause of death was strangulation
Who are the Laundrie family?
Mr Laundrie’s father, Chris Laundrie, 62, and mother Roberta Laundrie, 55, live in North Port. Mr Laundrie also has a sister, Cassie Laundrie, whose children Mr Laundrie and Ms Petito appear to have been close with.
Ms Laundrie appeared on ABC’s Good Morning America on 17 September, saying she had not spoken to her brother since he returned from his trip, but that Ms Petito was “like a sister and my children love her and all I want is for her to come home safe and sound and for this to be a big misunderstanding”.
Mr Laundrie’s parents also appear to have had a close relationship with Ms Petito, as she lived with them for more than a year, as Ms Petito’s mother outlined in an open letter to the Laundries when her daughter was still missing.
Roberta Laundrie was a Pinterest “collaborator” on a “Life Goals” Pinterest board created by Ms Petito that showed pictures of newlyweds with backpacks and posts of baby clothes.
Chris Laundrie eventually assisted the FBI in the search for his son, though his efforts proved fruitless.
What was his relationship to Gabby Petito?
Mr Laundrie met Ms Petito at Bayport-Blue Point High School on New York’s Long Island, according to Ms Petito’s stepfather, Jim Schmidt.
The pair began dating in March 2019 and got engaged in July 2020, according to posts on their Instagram accounts.
Mr Laundrie wrote: “My biggest fear is that one day I’ll wake up and it will have all been a dream, because that is what every second has felt like since the moment we found each other. Till death do us part or until I wake up, I’m so happy the answer was yes, Love you hunny.”
Ms Schmidt told The Daily Mail she believed the couple may have called off their engagement ahead of the trip because they were still so young.
Mr Laundrie himself always presented an idyllic picture of the couple’s relationship on social media, regularly posting pictures of them kissing and posing together smiling.
Eyeywitnesses though saw a very different side of Mr Laundrie’s treatment of his partner. He was allegedly seen slapping and hitting her in Moab City, Utah, on 12 August during a confrontation that lead one concerned onlooker to call 911.
Police later pulled their van over to find a crying and clearly distressed Ms Petito and Mr Laundrie with scratches on his face.
“We’ve just been fighting this morning. Personal issues,” Ms Petito told police.
One officer said in body-camera footage that they considered Mr Laundrie to be the victim, although not at risk, and no further action was taken.
What does he do for a living?
Mr Laundrie does not appear to have been in full-time employment but he did earn money selling artwork online.
On a Depop site called Bizarre Design, Mr Laundrie sold bookmarks, print stamps and T-shirts he designed himself .
What was his social media presence like?
Mr Laundrie presented himself online as outdoorsy, a loving and devoted boyfriend and an artist with slight conspiratorial leanings.
On Instagram, he railed against people being “brainwashed by the media” and revealed a fondness for pop culture icons such as Fight Club author Chuck Palahniuk and Mike Mignola, creator of the Hellboy comics.
His posts are sprinkled with references to nature and he expressed admiration for film characters like Joaquin Phoenix’s Joker, violent video games like Hotline Miami and the book Lullaby by Mr Palahniuk, in which a man investigates the death of his wife and child.