Brian Laundrie has admitted to murdering Gabby Petito in a notebook found near his remains, according to the FBI.
A recovered notebook containing a confession was discovered nearby Laundrie's remains in Florida’s Myakkahatchee Creek Environmental Park.
“A review of the notebook revealed written statements by Mr Laundrie claiming responsibility for Ms Petito’s death,” the FBI said in a statement.
FBI Denver Division Special Agent in Charge Michael Schneider said that 'the investigation quickly focused on the last person believed to see her alive — Mr Laundrie'.
The special agent said: "The FBI’s primary focus throughout the investigation was to bring justice to Gabby and her family."
Petito family attorney Richard Stafford thanked the FBI for its 'diligent and painstaking efforts in this extremely complicated case'.
The statement read: "The quality and quantity of the facts and information collected by the FBI leave no doubt that Brian Laundrie murdered Gabby."
Laundrie died from a self-inflicted gunshot wound to the head, his family's lawyer confirmed, last November.
According to The New York Post, a forensic anthropologist determined the cause of death to be suicide.
Attorney Steve Bertolino told the outlet: "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.
"Chris and Roberta are still mourning the loss of their son and are hopeful that these findings bring closure to both families."
Police said Laundrie's remains were submerged in the marshy park for weeks before they were found, which proved to be a challenge for coroners.
Authorities issued a statement, saying: "A comparison of dental records confirmed that the human remains found at the T. Mabry Carlton, Jr. Memorial Reserve and Myakkahatchee Creek Environmental Park are those of Brian Laundrie."
Laundrie was a 'person of interest' in the homicide of his late partner Petito, and was missing since September 14.
Previously, he and Petito had been travelling the national parks of the USA together, but Petito was reported missing and her body was later discovered in Grand Teton National Park in Wyoming.
The coroner revealed that her death was a homicide.
It was concluded that Petito was killed by strangulation.
Featured Image Credit: Credit: North Port PoliceTopics: World News