Earlier this month, Laundrie is said to have returned to the couple's Florida home alone.
Petito has blonde hair, blue eyes and has several tattoos. She is around 5 feet, 5 inches tall and 110 pounds.
North Port Police Chief Todd Garrison said at a press conference on Thursday, September 16, that the pair planned to travel in Petito's van to the West Coast on the road trip. "She maintained regular contact with her family members during her travels, however, that communication abruptly stopped around the end of August," he said.
The couple had an encounter with Utah police in August. According to PEOPLE, authorities released the body cam footage.
On August 12, someone called the police after the couple seemed to be arguing outside a food cooperative called Moonflower.
According to the footage, Petito tearfully told police that they had been fighting that morning and she had become frustrated with the 23-year-old earlier that day. Laundrie told police that once she became frustrated, he locked the doors to the van and suggested they go for a walk to cool off. He told officers that the scratches on his face and neck were because she was trying to get the keys from him and "got me with her phone" in the process.
The pair reportedly spent the night away from each other with Petitio in the van and Laundrie in a hotel.
Laundrie's lawyer is said to have refused to deny a potential link between Petito's disappearance and the murder of a couple in Utah.
Kylen Schulte worked in the Moonflower co-op. Days after Petito and Laundrie's incident, Schulte and her wife Cyrstal Turner were reportedly found shot dead at a local campsite. They are said to have text friends and said a man was allegedly "creeping them out," The Sun reported.
They were last seen at Woody’s Tavern in Moab on August 13. On Wednesday, September 15, a spokesperson for the Grand County Sherriff's Office told Fox News that they were "looking at everything" and were "not ruling anything out."
The Grand County Sheriff's Office announced in a press release on Thursday, September 16, that they have been "in contact with Florida authorities" and are "actively looking into any connection" between the two cases.
Laundrie is said to be a "person-of-interest" in Petito's case. His attorney, Steven Bertolino, said in a statement that law enforcement needs to follow protocol and leads. "Whether or not these two cases deserve to be linked will be determined at some point in the future," he said, per The Sun.
Petito's parents are said to have sent a letter to Laundrie's parents and begged them to tell them "where Brian left Gabby."
"As a parent how could you let us go through this pain and not help us," the letter read.
"Gabby lived with you for over a year. She was going to be your daughter in law. How can you keep her location hidden?" they wrote. "Please, if you or your family have any decency left, please tell us where Gabby is located. Tell us if we are even looking in the right place."
One of Petito's friends said that she blew off a meet-up and never phoned on her birthday. "[The] last time I talk [ed] to Gabby was the beginning of August when we were planning for me to meet her in Yellowstone after my birthday," the pal, who wishes to remain anonymous, told The Sun.
The friend said that Petito would never wander off and not contact her family: "She wouldn't blow me off either. She's my person. And I can't stop thinking about how scared she must be."
"She was supposed to call on my birthday and we were going to figure it all out then because her trip wasn’t on schedule," the friend explained of their meet-up.
Petito reportedly sent a text to her mom on August 30 where she said there was no service in Yosemite. However, according to the pal, Petito's family does not believe the text was sent by her.
Laundrie is said to have refused to cooperate with authorities, PEOPLE noted.
"We are pleading with anyone, including Brian, to share information with us on her whereabouts in the past few weeks," Garrison said in a statement on Wednesday, September 15. "The lack of information from Brian is hindering this investigation. The answers will eventually come out."
Petito's stepfather James Schmidt told the Daily Mail that Laundrie "has to know something": "She deserves to be found and brought home safe. And we need you to step up and do the right thing."