An FBI review of a notebook found near Brian Laundrie’s corpse revealed that he took responsibility for the death of his fiancée, Gabby Petito, the agency announced Friday.

The notebook, discovered alongside his corpse in a Florida wilderness reserve in October, “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 added: “The investigation did not identify any other individuals other than Brian Laundrie directly involved in the tragic death of Gabby Petito,” whose body was found strangled to death a month prior in Wyoming ― one of the couple’s stops on an extended, multi-state road trip they’d embarked on.

Since its discovery, the notebook has been a source of intrigue. Though it likely spent weeks underwater, the public was hopeful at least parts of it would still be legible and that it could provide useful information about the circumstances of Petito’s death.

Earlier this month, the Laundrie family’s attorney said his clients had “no inkling” about what it may contain and were seeking its return from police custody.

Laundrie was the only person of interest named in Petito’s disappearance and death, but law enforcement was not able to track him down before he died by a self-inflicted gunshot wound. His comments in the notebook, which the FBI did not detail, offer the most conclusive evidence yet that Laundrie, 23, killed Petito, 22.

The FBI says it will soon officially close the case, as all “logical investigative steps have been concluded.”

An attorney for the Petito family thanked the investigators, saying in a statement that they “truly appreciate the FBI’s diligent and painstaking efforts in this extremely complicated case. The quality and quantity of the facts and information collected by the FBI leave no doubt Brian Laundrie murdered Gabby,” it said.

The Laundrie family’s attorney told CNN that his clients and Petito’s parents have worked out an agreement on how to divide the notebook and the couple’s other belongings. Friday’s announcement should bring everyone peace, he added.

“We can only hope that with today’s closure of the case each family can begin to heal and move forward and find peace in and with the memories of their children,” he said. “May Gabby and Brian both rest in peace.”