Denver, Colorado - Brian Laundrie privately admitted that he killed his fiancée Gabby Petito, the FBI said Friday.

Laundrie (23) wrote about the killing in a notebook, the feds said. The notebook was found next to Laundrie’s body in a Florida nature reserve in October.

"A review of the notebook revealed written statements by Mr. Laundrie claiming responsibility for Ms. Petito’s death," the bureau said Friday in a press release.

The feds also said Laundrie faked text message exchanges with Petito after her death.

Shortly before the FBI shared its evidence, Petito’s family released a statement that said there was "no doubt" that "Brian Laundrie murdered Gabby." The family met with the FBI on Thursday.

Petito, who was 22 at the time, went on a cross-country trip with Laundrie, her fiancé from Florida, in the summer of 2021. When Laundrie arrived home in Florida without her in early September, a nationwide search ensued.

Petito, who was born and raised on Long Island, was found dead September 19 in Grand Teton National Park in Wyoming, and her death was ruled a homicide by strangulation. Laundrie was named a "person of interest" but then disappeared himself before ever speaking with police.

"While law enforcement investigated all logical leads, the investigation quickly focused on the last person believed to see her alive – Mr. Laundrie," the FBI said Friday.

On October 20, Laundrie was found dead in a Florida nature reserve. The FBI said Friday that when the Carlton Reserve near North Port was initially searched, the area where Laundrie’s body was later found was underwater. The FBI also confirmed that Laundrie died by suicide from a self-inflicted gunshot.

In August, police officers in Utah intervened in a domestic dispute between Petito and Laundrie. The cops simply told the couple to spend the night apart in the city of Moab, about 200 miles southeast of Salt Lake City.

"It’s very likely Gabby was a long-term victim of domestic violence, whether that be physically, mentally, and/or emotionally," wrote Price, Utah, police Captain Brandon Ratcliffe, in a report on the incident.