Bobby Mendiola
Bobby Mendiola has 30 years of Law Enforcement experience. He is a retired Sergeant with the San Jose Police Department.

Martin Deffenbaugh
Martin Deffenbaugh is a former U.S. Army MP and retired Sergeant from the Aurora, Colorado Police Department after 27 years on the road. Koga System instructor since 1987, certified in ACT, Self-Defense, Baton, SD-1. Crowd and riot control instructor.

Steve Norton
Steve was a Police Officer/Agent with the Aurora, Colorado Police Department for 29 years serving in a variety of assignments including patrol/FTO, investigations, training academy, Direct Action Response Team, and SWAT. Steve served on the Aurora PD SWAT Team for over 22 years and was a long time team leader. He is a two-time recipient of the Aurora Police Department’s Medal of Honor for SWAT hostage rescues.

Steve has been recognized as an expert witness in officer survival/use of force in Federal Court, Jefferson County Colorado District Court, and in an Arapahoe County Colorado Grand Jury officer involved shooting case. He was published in the National Tactical Officer’s Association SWAT journal, “The Tactical Edge” in the 2003 spring edition for an article on hostage rescue tactics.

Steve is a senior instructor with the Koga Institute in Arrest Control, Baton, Self Defense, and S-1 and is a senior level instructor in police ground tactics with Law Enforcement Ground Systems. He continues to instruct at the Community College of Aurora Law Enforcement Training Academy.

Chris Mimmack
Chris Mimmack began studying the Koga Method in 1992 as a deputy with the La Plata County Sheriff’s Office in Durango, Colorado. He started his Law Enforcement career as a jail deputy and transferred in to Patrol division in 1994. Chris worked in several different assignments at the Sheriff’s Office to include Patrol Sergeant, Special Investigations, Tactical team leader for SWAT and eventually Captain as the Jail Commander. At the Sheriff’s Office Chris achieved two Medals of Valor and a Badge of Merit as a Patrol Sergeant and SWAT Team Member.

Chris transferred to the Durango Police Department in 2007 and later to the Southern Ute Indian Tribe in 2009 and is currently the Detention Director for the Southern Ute Adult Detention Center. Chris became a Koga institute certified instructor in 1995 and has instructed officers in the method at each of the agencies he’s worked with as well as at the local police academy. He currently hosts and helps instruct three Instructor certification courses a year in the Four Corners area.

Mike Nottoli
Michael Nottoli is the Police Services Manager for the Rocklin Police Department. Michael has worked for the City of Rocklin since May of 2002, and is responsible for crime prevention, community education, and managing 124 Rocklin Police and Fire Volunteers.

Michael holds a Masters Degree in Public Administration and a Bachelors Degree in Criminal Justice from San Jose State University. Michael is married, has one son, and enjoys astronomy, amateur radio, martial arts, and exercising in his spare time. He also teaches civilian self-defense courses at Sierra College, and arrest control, self-defense and baton classes for the Koga Institute, a private law enforcement training organization.

Michael has been in law enforcement for 30 years, and enjoys working with and serving the Rocklin community. Prior to working in Rocklin, he worked as a Community Service Officer for the City of Saratoga, a Crime Prevention Specialist for the Fremont Police Department, and a police officer for the San Jose Police Department and the West Valley/Mission College District Police Department.

You may contact him by telephone at (916) 625-5416 or by email at

Don Black
Don Black retired from the Aurora, Colorado Police Department after 32 years of service out of a total of 37 years of law enforcement experience. He was active in all areas of police tactics and a number of martial arts. He has studied with Robert Koga for 35 years.

Don James
Don James is a retired Police Agent from the Aurora Police Department, Aurora, Colorado. He served with Aurora PD for 33 ½ years. His assignments included Patrol, FTO, Investigations and the Training academy. He was a member of SWAT for 31 years and was assigned to the full time SWAT unit. He was a team leader and received the department’s highest award (Medal of Honor) for his actions during a hostage rescue.

Don has studied under Sensei Robert Koga since 1979. Don has instructed Aurora Officers in all three disciplines (Arrest Control, Baton & Self Defense) since 1987. He continues to instruct at the Aurora Community College Law Enforcement Academy where he has served since 1995. Don also served as the President of the Aurora Police Association for 10 years, negotiating pay and benefit packages as well as representing officers in discipline matters.

Tom Boyce
Tom Boyce is a 25 yrs veteran of law enforcement. During that time he worked in Patrol, Detectives, 16 years in SWAT, and retired at the rank of Lieutenant. Tom became a student of Sensei Koga in 1987, staying involved ever since. Tom is also involved in aikido and several other martial arts.

John Austin
John Austin was born in March of 1962 to James and Helen Austin in upstate New York, he was the fourth of seven children. The Austin family moved to Richmond, California following James Austin’s 1968 retirement from the US. Army. John attended Salesian High School, Contra Costa College and the University of California Berkeley. John received his BA in Legal Studies from the School of Jurisprudence and Social Policy in 1984. He was hired by the San Francisco Bay Area Rapid Transit Police Department (BART PD) in January 1985.

In 1986 John joined the BART PD Arrest & Control Tactics instructor core and attended the Koga System ACT course in San Jose, Ca. John also served in the BART PD’s Field Training Officer corps, Detectives, SWAT team, bicycle team and Tactical Team.

John was promoted to sergeant in February 2001 and retired from BART PD in May 2012.John studied Judo from Sensei Mervin Tate and was eventually promoted to Yondan (4th degree) black belt. John was on the 1982 USA Pan American Judo team, John was also on 1981 USAJ Judo team to South Africa.

AC Cox
AC Cox has been involved in the Koga System as a student, teacher, and instructor for over 30 years, starting in 1984 when AC became a Police Officer with the City of Pomona, CA Police Department. AC began teaching the Koga System of Arrest and Control, Baton, and Self Defense to Officers when AC became an FTO in 1986. AC is currently a part time College Police Officer with MiraCosta College in Oceanside, CA, where AC is the Use of Force Instructor. AC is also a reserve Police Officer and Use of Force Instructor with the Pomona Police Department.

AC retired from full time duty at Pomona at the rank of Sergeant on August 1, 2010. During his 32 years with the Pomona Police Department AC worked various details and assignments such as patrol officer, patrol supervisor, Field Training Officer, Special Weapons and Tactics Operator for 14 years, Major Crimes Task Force Unit as an Officer and as a Supervisor, and AC was the Field Training Officer Program Coordinator the last three years prior to his retirement. AC currently trains new and current instructors in the Koga System for the Koga Institute for the past five years.

Robert K. Koga
Left to right: Senior Instructor Charles Watts, Sensei Robert Koga, Senior Instructor Don Black.

Tim Bergmann
Tim Bergmann is retired from the Pomona Police Department with 24 years of experience. He has been teaching Koga techniques for 26 years (11 years at Rio Hondo Police Academy). Tim has been a use of force instructor for 22 years. He was a member of S.W.A.T. for 10 years, a firearms Instructor for 18 years, a chemical agent Instructor for 18 years, a supervisor for 13 years, and a K9-Handler for 4 years.

Charles Watts
Charles Watts started his training with the Koga Institute in 1978. During his tenure Charles spent countless hours in the personal company of Sensei Robert Koga. His years of training resulted in Charles attaining the level of Senior Staff Instructor with the Koga Institute.

Charles joined the Pomona Police Department in 1972 and was promoted to Sergeant in 1979. He attained the rank of Lieutenant in 1992. In 1991 Charles graduated from the FBI National Police Academy Class #167 located in Quantico, Virginia.

During his career Charles served as a Patrol Officer, Field-Training Officer, School Resource Officer, Major Crimes Task Force Sergeant (MCTF), Detective Sergeant, Training Sergeant, Training Lieutenant and as a Patrol Watch Commander. Charles spent more than 20 years actively developing and leading the department’s Arrest Control and Use of Force program efforts. He retired from Pomona Police department in 2002.

For 25 years Charles also was one of the lead instructors for the Defensive Tactics/Arrest & Control training at Rio Hondo Police Academy in Whittier California. Charles has also trained in Kung Fu San Soo and Aikido.

Don Finkbiner
On January 3rd, 1990, Don was hired as a fulltime police officer. Don served as a Crime Scene Investigator and two tours as a School Resource Officer. Additionally, Don served as one of the Department’s first Gang Enforcement Officer, during which time he was deputized as a U.S. Marshal in order to work state criminal crimes in a federal capacity. He was also a Field Training Officer for both reserve and fulltime officers and was an Assistant Team Leader on the Department’s Mobile Field Force (crowd control) Team.

Don has also studied Tang Soo Don and Kenpo karate. In 1996 he became a use of force instructor for the Chico Police Department instructing officers in Arrest and Control, Defensive Tactics as well as Baton techniques. He first met Robert Koga in 1993.Don is currently an advisor for the Department's Explorer program and assists with Administration of Justice classes at two local high schools.

Don is an instructor at the Butte Regional Police Academy which he has done since 2000. Don retired after 24 years with the Chico Police Department.