By September 17, the Laundrie family admitted that they had not seen their son for some days, after at first refusing to speak with the police, via Insider. The very next day a manhunt commenced, including both local Florida law enforcement agencies and the FBI, per CNN. At that point, the FBI had yet to find Petito’s remains and they continued to search for signs of the young woman in Wyoming, primarily focusing on Grand Teton National Park. By September 19, human remains had been found in that area, which were later determined to be Petito’s. Those conclusions were confirmed on September 21 by the Teton County coroner, and an arrest warrant was issued for Laundrie. It was officially ruled that Petito had been strangled, also according to CNN’s report

In an effort to find Brian Laundrie, authorities searched a nearby nature reserve where his parents said their son had gone camping after he had arrived back in Florida, and where he said he was going when he subsequently disappeared.  At that point, Laundrie was wanted not just for questioning regarding the death of Petito, but for also using the young woman’s debit card and PIN after it’s believed she had died. By October 20, items that were believed to be Laundrie’s as well as human remains were discovered at the Carlton Reserve where authorities were searching. The next day those remains were confirmed to be Laundrie’s.