- Gabby Petito's family said FBI evidence leaves "no doubt" that her fiancé Brian Laundrie "murdered" her.
- Petito's body was discovered at a remote campsite in Wyoming on September 19. She was stranged to death.
- Laundrie's remains were found in Florida a month later. He died by suicide.
Gabby Petito's family said on Friday that evidence gathered by the FBI leaves "no doubt" that the young woman's fiancé Brian Laundrie — who was the sole person of interest in connection to Petito's disappearance — "murdered" her.
"We truly appreciate the FBI's diligent and painstaking efforts in this extremely complicated case," Richard Stafford, an attorney representing Petito's family, said in a statement.
The statement added, "The quality and quantity of facts and information collected by the FBI leave no doubt [that] Brian Laundrie murdered Gabby."
An attorney for Laundrie's family declined to comment to Insider on Friday.
Petito's body was discovered at a remote campsite in Wyoming on September 19. She and Laundrie had embarked on a cross-country road trip out West in a converted camper van last summer, documenting their travels on social media along the way.
A coroner determined Petito, 22, was strangled to death.
Laundrie vanished nearly two weeks after he returned from the trip to the Florida home the couple shared with his parents without Petito on September 1.
His skeletal remains were discovered on October 20 near his backpack at Florida's vast Carlton Reserve. He died by suicide, a medical examiner found.
Laundrie, 23, was never charged in connection to Petito's killing.
A US district court issued an arrest warrant for Laundrie on a charge related to bank card fraud in September, and he was the subject of a massive FBI-led manhunt before his remains were discovered.
The FBI did not immediately respond to a request for comment by Insider on Friday.
In Stafford's statement on Friday, he noted that Petito's family "would like to thank" the FBI, including its Wyoming, Denver, New York and Tampa offices, "all of their task force members and their assisting agencies."
"Gabby's family would like to thank the FBI's Victim Services Department for all they have done for them," Stafford said. "Victim Services has been there for support from the earliest stages of this investigation and helped their entire family navigate through the worst moments of their lives."
This story is developing. Please check back for updates.