Dunno, Gary. Here's his bio:
DENNIS B. TUELLER: A 25-year veteran (Lieutenant, retired) of the Salt Lake City, Utah Police Department where he made significant contributions to firearms policy and training. He was a Senior Staff Instructor at "Orange" GUNSITE, and is currently a member of the Guest Staff at THUNDER RANCH. Also a former member of Board of Directors of the International Association of Law Enforcement Firearms Instructors, he has been a frequent presenter at IALEFI Training Conferences in the United States and Europe.
He lives here in Utah.