[3] Following graduation in 1966, Keppel worked for the King County Sheriff's Office before being drafted as an Army drill sergeant and a captain in the Vietnam War from 1967 to 1974.
Witnesses from Lake Sammamish State Park provided information regarding a man named "Ted" who had talked to two young women that were declared missing.
[1] Keppel was asked to assist in the Green River Task Force for the investigation of a set of murders in Washington.
By 1984, Ted Bundy began writing letters to Robert Keppel in hopes to help in the investigation of the Green River Killer.
As of 2004[update], Keppel was an associate professor of criminal justice at Sam Houston State University, and taught there via teleconference.