Neighbors reported seeing a small red car circling Trisha's home the week before she disappeared. She was seen getting out of a small red car a few days before she vanished. On the day she disappeared, a clerk at the Welcome Mart a few miles from Autry's home, saw a young girl whom she believes was Trisha in the store. She was looking out the window as though waiting for someone. The clerk was concerned and asked her if she was all right. The girl replied that she was and left without buying anything. There were several other sightings of Trisha in Utah over the next few months that police followed up in the hope that Trisha was still alive.

UPDATE: In May 2001 police discovered Trisha's remains at the Predator Research Facility in Millville Utah, 8 miles from Hyrum. Police had become suspicious of the activities of a local 28-year-old man, Cody Lynn Neilson, a maintenance man at the facility. He had been seen digging trenches with a backhoe shortly after Trisha vanished. With the help of cadaver dogs, her remains were discovered buried in trenches in several locations on the facility grounds. Soon after, another 15-year old Hyrum girl and friend of Trisha's came forward and told police that she had been raped by Neilson. She told police that Neilson had given Trisha his cell phone number. Cody Lynn Nielson was convicted of the murder of Trisha Ann Autry and was sentenced to life in prison without parole.