Gavan McMahon is a retired Senior Law Enforcement Officer with Australian Customs and Border Protection, with over 40 years of service and operational command experience. Gavan has conducted extensive research into various aspects of the 1963 assassination of President John F. Kennedy. His most recent research focuses on the shooting death of Dallas Police Officer J.D. Tippit and the likely conspiracy and cover-up involving members of the Dallas Police and organized crime. He has conducted extensive interviews with the family members of Helen Markham and William Scoggins, witnesses to the Officer Tippit shooting, and has published articles on these findings in "garrison - The Journal of History and Deep Politics."