The revelation is the FBI's final investigative update to the Petito case.
Brian Laundrie was solely responsible for the death of Gabby Petito, the FBI announced on Friday.
Federal investigators concluded that the probe surrounding Petito's death "did not identify any other individuals other than Brian Laundrie directly involved in the tragic death of Gabby Petito." According to the FBI, the agency made the determination after discovering a journal entry in which Laundrie took "responsibility" for the death of his girlfriend.
Following the discovery of human remains that were later confirmed to be that of Laundrie's, the FBI said further search of the area on Oct. 20 also turned up a backpack, a notebook and a gun. "A review of the notebook revealed written statements by Mr. Laundrie claiming responsibility for Ms. Petito's death," the FBI said in a statement.
The agency also said Petito's family met with the FBI in its Tampa, Florida, field office on Thursday, adding that the case into Petito's disappearance and death will soon be closed.
"All logical investigative steps have been concluded in this case," said FBI Special Agent in Charge Michael Schneider, who on behalf of the FBI, also expressed "my deepest appreciation to the public for the thousands of tips that were provided during the investigation, and to our local, state and federal law enforcement partners for their work throughout the investigation."
The latest, and final, development in the Petito case comes nearly two months after Laundrie's cause of death -- a gunshot wound to the head -- was revealed by the Laundrie family attorney, Steven Bertolino. The manner of death was ruled a suicide. His body was found in Myakkahatchee Creek Environmental Park in North Port, Florida. Laundrie's dental records helped the FBI confirm the remains they found were those of Laundrie.
About a week before authorities found Laundrie's remains in October, a Wyoming coroner revealed Petito's cause of death was determined to be from strangulation. The manner of the death was ruled a homicide. At that time, there was a manhunt well underway to find Laundrie, who had gone missing shortly after Petito was reported missing.
Petito was an influencer who documented her and Laundrie's cross-country trek on social media. Her disappearance drew national headlines after Laundrie returned to his parents' Florida home with Petito's van but without her.