Brian Laundrie's Parents 'Have No Inkling' What Might Be in Notebook Found Near Remains: Lawyer

"I am sure everybody is waiting to find out what, if anything, is contained in the notebook," Steven Bertolino tells PEOPLE

The contents of Brian Laundrie's notebook — found this week in the Myakkahatchee Creek Environmental Park, alongside his body and his backpack — remain a mystery, even to the 23-year-old's parents, their lawyer says.

PEOPLE spoke to attorney Steven Bertolino on Friday, who said Christopher and Roberta Laundrie "have no inkling as to what may or may not be in there."

He added: "I am sure everybody is waiting to find out what, if anything, is contained in the notebook."

Laundrie was last seen on Sept. 13, as he was leaving his parents' North Port, Fla., home. Six days later, authorities found the body of his missing fiancée, Gabby Petito, in Wyoming's Grand Teton National Park.

Skeletal remains found Wednesday — just over a month after the discovery of Petito's body — were identified as Laundrie's on Thursday.

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At this time, it is unclear how Laundrie died, or how long ago.

The notebook and backpack were located near Laundrie's body, in an area of the park previously submerged under water three feet deep.

Laundrie's parents had assisted authorities in Wednesday's search.

Bertolino tells PEOPLE the remains were found along a trail Laundrie frequented, and only "about 20 to 30 minutes into the walk."

According to Bertolino, Laundrie was "definitely upset" when he returned home on Sept. 1 without Petito.

"He was out of sorts at the time between when he came home and when he went to the hike and the day he went for the hike, he was extremely upset," the attorney explains. "Brian was very upset and distressed. Mr. Laundrie tried to prevent him from leaving the house in that condition and he couldn't, and Brian insisted on going out for the hike."

Bertolino said Laundrie was "depressed, distressed, and upset" after returning to Florida — "however you would describe somebody who is just not appearing to be in a good state of mind," he added.

Bertolino says Laundrie's parents are "devastated," and that they have no plans for a service as of now.

Gabby Petito, Brian Laundrie. Find Gabby/Facebook

"They haven't talked about anything beyond waiting to find out cause of death," he says, noting that, if they do decide to have a private funeral, they would not publicize that information.

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When asked if his clients have been put in a "tough spot" because of their son's actions, Bertolino says, "Of course."

"The press facilitated this circus," Bertolino says. "The press gave people-pundits and so-called experts the platform to espouse ideas that the parents were somehow helping him, somehow complicit, and they took two innocent people and basically conducted a Salem witch hunt."

Gabby Petito, Brian Laundrie. Gabby Petito Instagram

Asked outright about Petito's killing and whether Brian admitted anything to his clients, Bertolino says, "That is not for discussion right now ... I am not going to comment any further on anything in respect to Gabby."

Laundrie was named a person of interest in Petito's disappearance on Sept. 15 — two weeks after returning home alone.

The couple had spent the summer traveling across the country in a white van together, documenting their adventures on YouTube along the way.

Petito's family reported her missing on Sept. 11.