Mark is a Former national and internationally ranked Judo competitor and competitive shooter. He is also a Firearms training consultant and founded Specialized Tactical Training Unit (STTU) 1982 – to provide services for numerous law enforcement and military training contracts
Mark is also the author of several books to include Sniper Counter Sniper; CQB; Raids; Sniper II; Advanced Weapons Training for Hostage Rescue; SRT Diver; Alpine Operations; and United States Navy Diver.
He served as a Military Adviser, Defense Contractor and Senior Security Consultant in Iraq and Afghanistan 2001-2009. He has also been a guest lecturer at the US Army War College and several universities; Masters degree - Criminology with a focus on the Criminal Components of Insurgency and Terrorism.