CNN  — 

Many questions remain unanswered following the death of Brian Laundrie. But crime experts say the notebook found near his remains in a Florida nature reserve park may shed some light on the circumstances of his disappearance and the violent death of his fiancée, Gabby Petito.

The FBI confirmed Thursday the remains found in Carlton Reserve in North Port belonged to Laundrie – who vanished last month after Petito was reported missing. She was found strangled in a Wyoming national park on September 19.

Law enforcement also found some of Laundrie’s personal items in the reserve, including a backpack, a notebook, a dry bag and some clothing.

Laundrie was not charged in Petito’s death, although the FBI on Wednesday had described him as a “person of interest” in her murder.

Experts told CNN the notebook believed to be Laundrie’s could offer some insight into a story that has grabbed public attention.

“If that notebook contained, for example, information that could have been admissions, it could be projecting blame or rationalization, all that information could help in the determination,” former FBI profiler Jim Clemente said Thursday.

A source with knowledge of the investigation told CNN the notebook was clearly wet when it was found outside a dry bag authorities located Wednesday during their search. But it is “possibly salvageable,” the source said.

“They are going to use any potential means to dry that out before opening it,” the source said. “They’ll be very careful with it.”

Mark O’Mara, a criminal defense attorney and former prosecutor, told CNN the FBI will have “some luck” retaining some of the notebook due to the advancements of forensic technology.

“So I think there’s going to be great information to come from that. Because even if there is bleeding amongst the ink and the pages, they have done a great job with even much older items that they find,” O’Mara explained.

Laundrie’s family doesn’t know what’s in the notebook, Steven Bertolino, an attorney for the family, told ABC’s “Good Morning America” Friday. Laundrie’s father picked up the bag that was found and immediately turned it over to law enforcement, he said, adding he didn’t know if the notebook was in the bag or in the backpack law enforcement found.

Authorities had been searching for Laundrie, 23, for more than a month. He left his parents’ home the week after Petito’s parents raised the alarm about her disappearance. They had been traveling across the US during the summer.

Asked whether Laundrie told his parents anything about Petito before he disappeared, Bertolino said it was “Not something I can comment on right now.”

The family has been cooperating with the FBI in terms of Brian’s disappearance “from Day 1,” the lawyer said. But he said, “We have absolutely nothing to say with respect to the Gabby Petito incident.”

Bertolino told CNN he talked with Brian Laundrie on September 12 and 13 but the content of those discussions is privileged information.

Determining cause of death can be tricky

But determining Laundrie’s cause of death could be challenging as authorities recovered only his skeletal remains and identified him through dental records, the FBI said.

His remains have been given to a forensic anthropologist, Bertolino said Friday.

Clemente, the former FBI profiler, told CNN it is a possibility Laundrie could have been dead for the entire month authorities have been searching for him.

“It’s going to be much more difficult to make a good, solid determination as to the cause and manner of death unless there’s some kind of major, serious trauma to the skull that can be identified,” Clemente explained.

“There might not be a way to determine how he died. If he drowned, for example, there wouldn’t be any evidence of that on his skeleton.”

Shortly before the FBI went public with identifying the remains, two local detectives visited the North Port home of Laundrie’s parents.

“Chris and Roberta Laundrie have been informed that the remains found yesterday in the reserve are indeed Brian’s,” Bertolino said Thursday. “We have no further comment at this time, and we ask that you respect the Laundrie’s privacy at this time.”

The parents joined the search Wednesday morning and found a bag belonging to their son at the park, which their family attorney described as “happenstance.”

“They kind of knew his favorite spots. They had told law enforcement from the beginning where Brian would most likely be, in the areas of the park,” Bertolino told “Good Morning America.”

The area was flooded when they looked earlier, he said.

Asked whether his parents think Brian Laundrie took his own life, Bertolino said he had discussed the possibility with them “several times.”

“We just do not know,” he said. “Of course, knowing his mental state when he walked out the door, it was always a concern.”

Speaking to CNN affiliate WABC on Thursday, the lawyer said the parents “knew that their, their son Brian was grieving.”

“Brian had been extremely upset,” Bertolino told “Good Morning America” when asked why his parents thought he was grieving. “They wish they could have stopped him, they wish they could have, you know, prevented him from going out, but he was intent on leaving.”

The parents are “a mess,” he told WABC. “They are extremely upset, they are extremely distraught is the word I’ve been using, but I don’t think that accurately describes it.”

The search has been “treacherous”

The exhaustive search for Laundrie stretched over a month after his parents told police they believed he’d gone to the reserve.

Lee County Sheriff Carmine Marceno said law enforcement had been searching in “treacherous conditions,” including nearly chest-high water full of snakes and alligators.

“These are very, very difficult conditions. You’re searching in areas that you just can’t walk up and look. It’s not like you’re searching a house or a car,” he said. “These areas are huge and they’re covered by water.”

Laundrie’s remains were found “about 2 to 3 miles inside the Carlton Reserve, or about a 45-minute walk” from the entrance at Myakkahatchee Creek Environmental Park, North Port police spokesperson Josh Taylor said.

The Myakkahatchee Creek Environmental Park is on 160 acres of heavily wooded land in North Port, with trails and a camping area. The park connects to the Carlton Reserve, a 25,000-acre nature reserve, which has been the primary search location for investigators.

Searchers had previously used swamp buggies, divers and airboats to scour the swampy terrain, but the area has dried out recently due to clearer weather.

CNN’s Steve Almasy, Rebekah Riess, Taylor Romine, Devon M. Sayers, Gregory Lemos, Nick Valencia and Theresa Waldrop contributed to this report.