Soon after returning to his parents’ home in North Port, Fla., without his fiancée, Gabby Petito, Brian Laundrie obtained a new phone, which is now in the possession of the FBI.
“To my knowledge, they did purchase a new phone and it’s the same phone that Brian left home and which the FBI is in possession of,” Bertolino told NewsNationNow.
It is unclear exactly when the phone was purchased, but it was sometime after Laundrie, 23, returned home without Petito, 22.
Petito, a Long Island, N.Y., native, was found dead on Sept. 19 in Grand Teton National Park in Wyoming, and officials have since determined her death was a homicide.
Petito was last seen in late August, while on a cross-country road trip with Laundrie.
For nearly two months, Petito and Laundrie had been traveling across America in a white, repurposed Ford Transit van. Petito was reported missing on Sept. 11 — more than two weeks after her mother last spoke to her by phone.
This week, Bertolino also confirmed that the Laundrie family had gone on a camping trip to Fort De Soto Park in Tierra Verde, Fla., on Sept. 6 and Sept. 7.
“They all left the park,” Bertolino said.
Bertolino did not immediately respond to PEOPLE’s requests for comment.
Visitor logs from the park confirm Roberta Laundrie, Brian’s mother, checked in to a waterfront campsite there for two days.
Bertolino has said that his clients have no idea where their son is.
Laundrie, who is a fugitive following the issuance last week of a warrant for his arrest, has not been seen since leaving his parents’ home for a hike more than two weeks ago.
The warrant accuses Laundrie of unauthorized use of a debit card. He was named a person of interest in Petito’s case, but has not been named a suspect in connection with her death.
Want to keep up with the latest crime coverage? Sign up for PEOPLE‘s free True Crime newsletter for breaking crime news, ongoing trial coverage and details of intriguing unsolved cases.
Laundrie and his parents refused to meet with detectives handling the case.
At this point, investigators have yet to say how Petito was killed, but believe she died sometime between Aug. 27 and Aug. 30.
Police believe the relationship between Petito and Laundrie became more strained during their tragic road trip, according to a newly unsealed search warrant connected to the case.
Petito’s best friend, Rose Davis, tells PEOPLE the couple’s relationship was “toxic,” and that Laundrie’s jealousy led to numerous fights.
On Sept. 15, PEOPLE spoke with Petito’s father, Joseph Petito, who said his daughter was “amazing.”
“She’s so artistic. She’s an amazing artist. She loves to draw,” he said. “She has a great eye with decorating … She’s that flower child type of personality. The old soul, you know?”
“If Woodstock was still going on, she’d still be there, man,” Joseph added. “She’s a hippie from the ’60s, all right? She’s a Beatles fan, round glasses … a free spirit.”
If you have information on this case, call 1-800-CALL-FBI (225-5324).