Brian Laundrie admitted killing ex-girlfriend Gabby Petito in a “suicide note” found near his remains, the FBI announced.
Petito, 22, was pronounced dead at a campground near Grand Teton National Park in northwestern Wyoming on September 19.
A coroner ruled that she had died three weeks earlier from “blunt-force injuries to the head and neck, with manual strangulation.”
Following a four-month investigation, the FBI say Brian Laundrie was “directly involved in the tragic death of Gabby Petito”.
Investigators added that 23-year-old Laundrie had sent messages to deceive people that Petito was still alive after he beat and strangled her in late August.
The FBI did not specify what, exactly, Laundrie had written in the notebook and in the texts he’d sent to mislead.
The texts were sent between Laundrie’s phone and Petito’s phone, according to the FBI statement.
“The timing and content of these messages are indicative of Mr. Laundrie attempting to deceive law enforcement by giving the impression that Ms. Petito was still alive,” the statement said.
Laundrie returned home to Florida in early September but went missing soon after.
In October, his parents found an item belonging to him in a nature preserve near their house.
Further searching turned up Laundrie’s remains, a revolver, backpack and the notebook.
Medical professionals determined Laundrie died of a self-inflicted gunshot wound.
Grand Teton was the last place the couple visited during a cross-country van trip last summer that ended with Laundrie mysteriously returning home alone in the vehicle.
Laundrie and Petito grew up on Long Island, New York, but were living in Florida in recent years.
In the weeks leading up to Ms Petito’s death, the couple had documented their picture-perfect van life on social media as they continued on their travels.
They crossed Colorado and on August 12 were stopped by police near Moab, Utah, after the two got into an argument.
