Brian Laundrie's Notebook Confession Reveals He Murdered Fiancée Gabby Petito

Following a grueling investigation, FBI Denver announced Friday that Brian Laundrie is believed to be responsible for 22-year-old Gabby Petito's murder.

Laundrie, 23, was named a person of interest in the disappearance of his fiancée on Sept. 15, though authorities failed to declare him a suspect in her murder before his death.

A notebook discovered alongside Laundrie's remains revealed written statements by Laundrie that took responsibility for Petito's death, the FBI stated.

"All logical investigative steps have been concluded in this case," FBI Denver Division Special Agent in Charge Michael Schneider said in Friday's statement. "The investigation did not identify any other individuals other than Brian Laundrie directly involved in the tragic death of Gabby Petito.

Laundrie and Petito had spent the summer traveling across the country in a white van together, documenting their adventures on YouTube along the way — but on Sept. 1, Laundrie quietly returned to his parents' home in North Port, Fla., without Petito.

Ten days later, the 22-year-old woman's family reported her missing.

For the first week of Petito's missing persons investigation, the Laundrie family refused to cooperate with authorities, directing all questions to their attorney, police said.

A week after the Petito case began, the Laundrie family spoke to the FBI for the first time — but not to talk about Petito.

Instead, Laundrie's parents wanted to alert investigators that their son, too, had gone missing. They claimed he was last seen on Sept. 13 after leaving their home "visibly upset" to hike in the nearby Carlton Reserve.

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The FBI and local Florida authorities quickly launched a search for Laundrie in the 25,000-acre nature preserve, wading waist-deep through snake- and alligator-infested swamps in some areas.

While police were trying to locate Laundrie in Florida, separate search teams continued looking for Petito in Wyoming — her last-known location.

On Sept. 19, Petito's body was discovered in Grand Teton National Park. Her death was declared a homicide by the county coroner shortly after, and on Oct. 12, it was revealed that she died from strangulation.

Days after Petito's body was discovered, the U.S. District Court of Wyoming issued a warrant for Laundrie's arrest in relation to activities that occurred after Petito's death — not for her death itself.

The FBI revealed that a federal grand jury charged him with using an unauthorized debit card with intent to fraud.

"While this warrant allows law enforcement to arrest Mr. Laundrie, the FBI and our partners across the country continue to investigate the facts and circumstances of Ms. Petito's homicide," FBI Denver wrote in a statement on Sept. 23.

Laundrie was never arrested on the Wyoming charges, or charged with the disappearance and murder of Petito. On Oct. 20, his remains were discovered in a Florida nature park alongside his backpack and notebook.

With authorities naming Laundrie the sole person connected to Petito's death, the months-long case that captivated the nation has come to a close.