

He has done numerous studies involving the willing victims of sexual sadists (wives and girlfriends) and how sexual sadists appear in everyday life. He has conducted numerous studies on sex crimes and the behavior of autoerotic asphyxiation. Hazelwood has also offered the theory that there is no cure for pedophilia or sexual sadists. Of the six, anger excitation is by far the most dangerous and the hardest to capture. He also defined the six categories of rapists: power-reassurance, power assertive, anger retaliatory, anger excitation, opportunistic, and gang. In 1980, he developed the distinction between "organized" and "disorganized" murderers, a concept that is still used by law enforcement to help in the apprehension of criminals. He followed his tour with a forensic medicine fellowship with the Armed Forces Institute of Pathology (AFIP) and a stint with the CID as an instructor. He served a tour in Vietnam, which he completed in 1968 as a Major.

He was raised by his mother and stepfather in Spring Branch, Texas, and attended Sam Houston State University.

When he was an infant, his biological father, Myrle Reddick, kidnapped him and travelled around with him for six months before returning the boy to his paternal grandparents father and son never saw each other again. Roy Hazelwood was born in Pocatello, Idaho.
