Due to a similar modus operandi, McCoy has been proposed as the person responsible for the November 1971 hijacking of Northwest Orient Airlines Flight 305, attributed to the still-unidentified "D. B.

In 1962 McCoy moved to Provo, Utah, and enrolled at Brigham Young University (BYU) before dropping out to serve a two-year tour of duty in the Army.

[5] On April 7, 1972, McCoy, using the alias "James Johnson," boarded United Airlines Flight 855, a Boeing 727-22C (Registration: N7426U) en route from Newark, New Jersey to Los Angeles.

McCoy boarded the plane, which carried 85 passengers and a crew of six, including pilot Captain Jerry Hearn, during a stopover in Denver.

McCoy was on National Guard duty flying one of the helicopters involved in the search for the hijacker.

Inside his house, FBI agents found a jumpsuit and a duffel bag filled with cash totaling $499,970.

[10] He and a crew of convicts (Joseph Havel, Larry L. Bagley, and Melvin Dale Walker) escaped on August 10, 1974, by commandeering a garbage truck and crashing it through the prison's main gate.

News reports stated that on November 9, 1974, McCoy walked into his home and was met by FBI agents Nick O'Hara, Kevin McPartland, and Gerald Houlihan;[13] he fired at them, and all agents opened fire, killing McCoy.

Melvin Dale Walker tried to flee in their getaway car but he was apprehended after a short car chase by FBI Agents Richard Rafferty and Henry Bolin Jr.[14] 1991 saw the publication of D. B. Cooper: The Real McCoy, by Chief Probation Officer Bernie A. Rhodes Jr. and FBI agent Russell P. Calame.