Gabby Petito and Brian Laundrie on their road trip. Photo / Instagram

US woman Gabby Petito's close relationship with the family of her fiance is revealed in warm texts and postcards to his sister's children signed "Love Aunt Gabby".

The loving bond between the 22-year-old "Van Life" blogger, whose body is believed to have been found on Sunday, and her future in-laws is evident in messages she sent while on the road with her boyfriend. His whereabouts are still unknown.

The touching messages are in stark contrast with the cold reception the family of her fiance Brian Laundrie has given police since human remains, believed to be Petito's, were discovered in a Wyoming forest on Sunday.

Police and the FBI are still searching for Laundrie, 23, after his parents refused to let police talk to him at their Florida home. He vanished three days ago.

Roberta, 55, and Chris Laundrie have now returned to their North Port home on Florida's Gulf Coast after the FBI searched it.

And the Laundrie family attorney – who originally met police to deny them the interview with Laundrie before he vanished – cancelled a scheduled press conference.

Wild rumours have put Laundrie at numerous locations around the US and possibly even in the US Caribbean territory of Puerto Rico.

Stories about his alleged controlling behaviour with Petito have marred the image of the idyllic life of the carefree young couple pursing their travel dreams in a camper van across America.

A police report of the couple fighting and an eyewitness account of Laundrie "grabbing [Gabby's] face" in the days before Petito's death have put a different slant on their relationship.

But Petito's cheerfulness and kind thoughts for her boyfriend's nephews shine through in her messages to them on the road.

Gabrielle "Gabby" Petito met Laundrie in the town of Bayport in New York State's Long Island. They became engaged in July 2020 and the couple moved to his parents' North Port home. They set off to see the US' most iconic locations on July 2, 2021.

They travelled in a white 2012 Ford Transit van with Florida licence plates belonging to Petito who uploaded photos and videos on her Instagram page and blog posts about their travels.

The images showed a young couple kissing in spectacular locations and camping under the stars in America's great national parks.

As Laundrie's older sister Cassandra recently told TV show Good Morning America, Petito's tone in her messages to her and her children was enthusiastic.

"Ahh oh my gosh I can't believe school started already!!! Ha ha I saw your post on Instagram! So cute!! Send me the picture of the boys to show Brian!! Lol and I love their backpacks too!!" Petito texted Cassandra on August 10.

'Love Aunt Gabby'

In the text, which apparently referred to the Arches National Park north of Moab in Utah, Petito wrote: "We're in arches [sic] right now so we don't have be [sic] best Wi-Fi, but we did send you some mail."

Petito sent postcards from Utah's Goblin Valley State Park and Red Canyon, Good Morning America reported.

"Guess what!! Oh my Gosh! Me and uncle Brian were sitting on a Rock eating a snack after our long walk, and the fattest Squirrel I've ever seen!!!" the postcard in Petito's handwriting reads.

"Came Right on my lap!! And with its tiny Hands Stole a piece of the granola bar I was eating!! Can you Believe it!"

In another postcard, Petito writes "Uncle Brian and I miss you so much … the sky here is so open, there's more stars than I've ever seen!!".

"Love Aunt Gabby," one off the postcards is signed off.

But the upbeat tone may have masked something more sinister.

On August 12, Utah police in Moab conducted a roadside interview on bodycam of Petito and Laundrie.

In the since released footage, Petito appears to be crying while sitting in the back of a police vehicle.

Police said they pulled the couple over after the van veered off course and hit a bump on the side of the road.

The couple admitted arguing, reported the US ABC TV network. They said Petito had slapped Laundrie after an argument, according to the police report, and denied that Laundrie had hit his girlfriend.

"We've just been fighting this morning, some personal issues," bodycam video shows Petito tell police.

The Independent reported that a second officer said an eyewitness mentioned Laundrie had "grabbed [Gabby's] face and pushed her back" during the altercation.

"No one reported that the male struck the female, both reported they are in love and engaged to be married and desperately didn't wish to see anyone charged with a crime."

Petito told police she suffered severe anxiety and other medical conditions, which were redacted from the police report, and that the couple's argument had been building for days. Police labelled the incident as a "mental/emotional break" rather than a domestic assault, according to the report.

Petito's family said she maintained regular contact with them throughout the journey,
but communication from her "abruptly stopped" near the end of August.

She was last seen leaving a Utah hotel with Laundrie on August 24 and spoke with her mother, Nichole Schmidt, the next day.

She told Schmidt the couple were planning to visit Grand Teton and Yellowstone national parks.

"She sounded good and excited to continue her trip and excited to start her YouTube channel," Schmidt told ABC News.

But then she received two text messages from her daughter's phone, which were "odd" and unlike Petito. Schmidt now doubts her daughter actually sent those texts.

On August 27, a text from Petito's phone read: "Can you help Stan, I just keep getting his voicemails and missed calls."

Although Petito's grandfather is named Stan, Schmidt said her daughter never called him Stan.

By this time, Petito's mobile phone was no longer operating and she had ceased posting on her social media pages.

According to the Florida Police search warrant for Laundrie's computer hard drive, Petito had sent "multiple text messages" and "had many talks" with Schmidt during the trip.

"During these conversations there appeared to be more and more tension between her and Mr Laundrie," the warrant states.

On September 1, 2021, Laundrie drove the van up to his family's Florida home without Petito.

Ten days later, on September 11, Petito's family reported her missing. Florida Police knocked on the door of Laundrie's parents' home on the same day.

His parents later reported they had not seen him since September 14.

The Laundries run the business Juicer Services Inc, selling wheatgrass, orange and vegetable juicers from their home.

The couple had previously run a beverage vending machine business from Bayport, Long island and Laundrie worked at an organic juice bar. Petito told Utah police she was a "nutritionist".

On the day Roberta and Chris Laundrie refused North Port Police Department officers entry to their home, they seized Petito's Fort Transit van from the home.

It wasn't until September 17 that the family told police that Laundrie hadn't been seen since September 14.

On September 20, FBI investigators escorted the couple from the North Port home for questioning and searched the premises.

In her Good Morning America interview on Friday, Cassandra Laundrie admitted she hadn't spoken to her brother after he returned to Florida in the couple's van without Petito.

"I haven't been able to talk to him. I wish I had information where I could give more."