Darwin Vest, 48, vanished in the early hours of June 2, 1999, after leaving the Golden Crown Lounge in Idaho Falls. He had spent the evening at a trivia night at the Frosty Gator and later went to the Golden Crown for a nightcap. Vest left alone in the rain, declined a taxi, and was last seen around 1 a.m.; he never reached home or contacted family.

A self-taught toxinologist known for work on venomous spiders and snakes, especially the hobo spider, Vest had collaborated with law enforcement and testified in courts. His disappearance was out of character and followed a violent assault he suffered in 1997, which some have speculated could be connected, though no evidence has linked the two events. Authorities also investigated the possibility he fell into the Snake River after a witness reported seeing a body, but searches turned up nothing and his family disputes the river route and the idea he would walk in that rain.

Declared legally dead in 2004, Vest’s case remains unresolved. Can anyone who knew Vest or was in Idaho Falls that night add details that might help explain what happened?