The Killing House by Gayle Rivers
The truth about a member of Britain's elite Special Air Services told as fiction by Gayle Rivers who has served many governments and began with the SAS in Vietnam, on attachment to the US Special Forces. Captain Tim Bell has dedicated his life to becoming a reflex-efficient killing machine using his talents to battle terrorism around the world. Something inside him has snapped. Expelled from the SAS and using top-secret information filched from the files of his old US military buddy, Captain Bob Yardley, Bell has formed a hate-twisted strategy that no one can ignore. While Bell is training a vicious attack force in the desolate woods of Idaho, Bob Yardley realizes just how deadly his old friend has become and sees that he is the only man who knows Bell well enough to stop him. The author has also written "The Specialist" and "The Five Fingers".