Originally Published: 28 SEP 21 03:39 ET

Updated: 28 SEP 21 14:02 ET

By Eric Levenson and Madeline Holcombe, CNN

(CNN) -- An attorney for Gabby Petito's family expressed skepticism Tuesday that the parents of her fiancé Brian Laundrie would help in the FBI's ongoing search for him.

"The Laundrie's did not help us find Gabby. They're sure not going to help us find Brian," family attorney Richard Stafford said. "For Brian, we're asking you to turn yourself in to the FBI or the nearest law enforcement agency."

Speaking at a news conference alongside Petito's parents and stepparents, Stafford said the FBI had asked them not to discuss the relationship between the families. He said they were confident the FBI would thoroughly investigate the case and get justice for Petito.

Petito's parents and stepparents also announced the creation of the Gabby Petito Foundation, which they said would help keep alive her memory and help families in similar situations. And they revealed they got matching tattoos Monday night reading, "Let it be," in a script that their daughter designed.

"I wanted to have her with me all the time," her mother Nicole Schmidt said.

For their part, Laundrie's parents affirmed they do not know his whereabouts two weeks after he was last seen, their attorney said in a statement Monday night.

"Chris and Roberta Laundrie do not know where Brian is. They are concerned about Brian and hope the FBI can locate him," attorney Steven Bertolino said. "The speculation by the public and some in the press that the parents assisted Brian in leaving the family home or in avoiding arrest on a warrant that was issued after Brian had already been missing for several days is just wrong."

The statements come amid the deepening mystery over what happened to Petito, 22, and Laundrie, 23, who spent their summer traveling in a white van through the American West while she posted about their adventures across social media.

Those posts abruptly stopped in late August, and Laundrie returned to his parents' home in North Port, Florida, with the van but without his fiancée on September 1, according to police. Petito's family, unable to get in touch with her, reported her missing on September 11.

Petito's remains were found in a camping area in Wyoming's Bridger-Teton National Forest last week near where the couple had last been seen, and a coroner ruled her death a homicide.

Meanwhile, Laundrie's parents told investigators on September 17 they had last seen him three days earlier when he left home with a backpack, saying he was going to the nearby Carlton Reserve, a sprawling swampland that stretches over 25,000 acres in southwest Florida, authorities said. A source close to the family told CNN that Laundrie left his parents' home without his cell phone and wallet and his parents were concerned that he might hurt himself.

Local police spent more than 10 days unsuccessfully combing through the Carlton Reserve. The FBI, which has taken over the case, is leading a more targeted search based on intelligence, North Point Police said, and agents visited his parents' home to get personal items that would assist with DNA matching.

Laundrie has not been explicitly connected to Petito's death. Still, a federal warrant for his arrest accuses him of illegally using another person's debit card and PIN number on August 30 and September 1.

The unanswered questions about what happened to Petito have spurred digital detectives to comb through the couple's online trail to try to solve the case and surfaced reports that tension may have been building between the couple. The focus on Petito's case has also highlighted the tens of thousands of missing persons' cases across the country and raised questions about why some of those cases garner such intense interest and others do not.

Search for Laundrie ongoing

Laundrie returned to the Florida home he shared with his parents on September 1 without Petito, and authorities have been looking for him to provide answers.

Initially, he wasn't wanted on any charges, but Laundrie now faces a federal warrant for his arrest for the "use of unauthorized devices" stemming from his alleged actions following Petito's death. Laundrie allegedly used a debit card and PIN number for accounts that did not belong to him for charges exceeding $1,000 between the dates of August 30 and September 1, according to a federal indictment.

An attorney for Laundrie's family emphasized in a statement that the warrant was not for Petito's death but related to activities that allegedly took place afterward.

Two separate rewards totaling $30,000 have been offered to anyone who provides law enforcement officials with Laundrie's whereabouts.

FBI agents returned to the Laundrie home Sunday, as seen in video shot by CNN. At least two agents could be seen at the home and one had a bag in his hand.

During the agency's visit to the family home, "The FBI requested some personal items belonging to Brian Laundrie to assist them with DNA matching and Brian's parents provided the FBI with what they could," the Laundries' lawyer, Steven Bertolino, told multiple news outlets.

Dispatch audio sheds more light on a dispute

While their posts on social media portrayed a happy, sun-drenched life, an incident with police in August revealed significant issues in their relationship.

The first reports of conflict between the two came on August 12, when a 911 caller in Moab, Utah, told dispatchers he wanted to report a domestic dispute and described a white van with a Florida license plate.

"We drove by and the gentleman was slapping the girl," the caller said. He went on to say, "Then we stopped. They ran up and down the sidewalk. He proceeded to hit her, hopped in the car and they drove off."

CNN obtained dispatch audio recordings from the Grand County Sheriff's office Monday that shed more light on what Moab Police were told about "some sort of altercation."

According to the audio, the dispatcher told the officer that "a male hit a female" and that they got into a white Ford Transit van.

However, another witness, identified just by his first name, told investigators that Petito appeared to hit Laundrie in the arm and then climbed through the driver's side door as if he had locked her out, a Moab Police report states.

Police located the white van and initiated a stop near the entrance to Arches National Park. Petito and Laundrie were in the van.

In his police report, Officer Eric Pratt said Petito had slapped Laundrie, "who grabbed her face and pushed her back as she pressed upon him and the van."

Another responding officer, Daniel Robbins, said Petito had "gone into a manic state" when Laundrie tried to "separate from her so they could both calm their emotions." The officer reported seeing "minor visible scratches" on Laundrie's face.

Bodycam video of the incident shows Petito telling police, "We've just been fighting this morning -- going through some personal issues."

According to police, the officers suggested the couple go their separate ways that night and no charges were filed.

Moab Police Assistant Chief Braydon Palmer told CNN regarding the handling of the dispute on August 12, "We are reaching out to an outside agency to conduct that investigation." Palmer did not specify the agency.