[11][12] Found with Callahan's body were two scalped Grateful Dead tickets, a dollar in quarters, and a yellow Bic lighter.

A letter was found, depending on sources either in Callahan's pocket or near the crash site, reading: "Jason, Sorry we had to go, see ya around, call me #914-XXXX.

[7][11] At the time of the accident, he was wearing a red, tie-dyed Grateful Dead T-shirt, Levi's jeans, white socks and black Fila running shoes.

Neither of the decedents had drugs or alcohol in their bodies and there was no discernible external cause for the crash, so authorities hypothesized that Hager could have fallen asleep at the wheel.

[7][16] It has been suggested that Hager may have agreed to transport Callahan because of their similar styles of dress, as they both appeared to be fans of The Grateful Dead.

[8] Authorities attempted to identify Callahan through fingerprint analysis with the aid of national databases, but were unsuccessful.

[3] In 2015, photographs surfaced of a young man wearing similar clothes to those worn by the then-unidentified Callahan, and who bore a strong resemblance to the reconstruction images.

[5][18] In January 2015, law enforcement conducted a DNA test to see if the John Doe was the same man as Jason Patrick Callahan, the son of a 63-year-old woman who had not seen or heard from him since June 1995, when he left home to "follow the Grateful Dead".

[19] Callahan, who was identified as the young man in the photographs, is described as having been a white male with wavy blond hair and brown eyes, standing between 5 feet 10 inches (1.78 meters) and 6 feet (1.83 meters) tall, and weighing about 160 pounds (70 kilograms).