Immergan was last seen by his family in Savoonga, Alaska on November 2, 1999. He was planning to travel to Nome, Alaska. He has never been heard from again.

Prior to his disappearance, Immergan told his sister he had beaten on two occasions by police officers in Nome. The alleged assaults took place in 1998 and the spring of 1999. He refused to report the incidents and it is unknown whether they have anything to do with his later disappearance.

Approximately 20 Native Alaskan people have vanished or died under questionable circumstances in the Nome area since the 1960s. Authorites opened a probe into their deaths and disappearances, but they do not believe a serial predator was involved.