(CNN) -- Brian Laundrie died by suicide from a gunshot wound to the head, an attorney for the Laundrie family told CNN on Tuesday.
"Chris and Roberta Laundrie have been informed that the cause of death was a gunshot wound to the head and the manner of death was suicide," said attorney Steven Bertolino.
CNN has reached out to authorities for further comment, and has followed up with Bertolino regarding how Laundrie came to be in possession of a gun.
The couple had been traveling across the country over the summer in a converted van and documenting their travels on social media. The case gained national attention as authorities searched for both.
Laundrie returned to his parents' house in Florida on September 1 without Petito. As police were trying to question the family about Petito's whereabouts, Laundrie went missing on September 13 or 14 after leaving home with a backpack, according to his parents.
Petito's remains were found in Wyoming on September 19. Her death was ruled a homicide by manual strangulation.
What led to Petito's death remains a mystery. The FBI had described Laundrie as a "person of interest" in her murder, but he was not charged. He had, though, been indicted for allegedly using two accounts that belonged to someone else in the days after she died.
Laundrie's remains were found October 20 in an area of Carlton Reserve that had been under water during previous searches of the 25,000-acre nature reserve in North Port, Florida.
Laundrie's father, who was searching with authorities the day his son's remains were found, discovered a notebook near where Laundrie's body was found. Experts said at the time that the notebook could be key in providing answers.
The notebook was wet at the time, and officials haven't yet said whether they have gained any information from it.
Bertolini said in October that Laundrie's parents had discussed the possibility that their son had died by suicide "several times."