Kirchner was last seen in Coconino County, Arizona in early April 2007. He was hiking a remote section of the Navajo Reservation. He's an experienced hiker who's hiked extensively in the Colorado Plateau. Kirchner failed to meet a friend in Las Vegas, Nevada on April 9. The search for him began on April 12. That day, his vehicle was found in the Hellhole Bend area along the Little Colorado River Gorge. An extensive search turned up no other sign of Kirchner, however, and his case remains unsolved.