Supervision Team

Every law enforcement agency will tell you that the supervision core is the backbone of the department. Efficiency, effectiveness, and integrity of any organization relies in the hands of supervisors. They are the professionals who make sure the shift is running smoothly and assessing every aspect of the service being provided to the community. The Shafter Police Department has a great staff who we believe are among the best in the business. We'd like to use this forum to introduce them to you, their professional backgrounds, and their specialties.

​Captain Jeff Bell 


Captain Bell began his public service career in 1976, entering the United States Coast Guard. After Honorably discharging in 1980, he attended Ventura Community College. Graduating in 1984, he then began his law enforcement career starting with the Los Angeles County Park Police in the fall of 1984. He promoted to Sergeant in 1993 and has worked significant events such as the Ruby Canyon fire  of 1987, the 1992 Rodney King riots, the 1992 Gang Truce Rally, the 1993 Firestorms, and the 1994 Northridge earthquake.

Captain Bell came to Shafter in June of 1999. He has a POST Management level certificate and over 3,500 hours of recognized POST training. In 2008, Captain Bell was selected to be the first City of Shafter police officer to attend the FBI National Academy, class 235. He also received the first Kern County Law Enforcement Foundation "Administrator of the Year" award.

The Captain has various responsibilities overseeing background and internal affairs investigations, representing the agency as the POST liaison and Training Manager, Property room oversight, policy development and will assist in multiple areas as needed regarding special projects, special investigations, animal control, or other staff projects. 

Lieutenant Diana Burnett


Lieutenant Diana Burnett began her career with the City of Shafter in February of 1992. She was promoted to senior officer in July of 1996, Sergeant in August of 1998, and promoted to Lieutenant in March of 2014.

With over 2,500 hours of recognized POST training, she has earned certification from the State of California Peace Officers Standards and Training (POST) of basic,intermediate, advanced, and supervisory. She also holds two certifications from the Robert Presley Institute of Criminal Investigations in Homicide and Domestic Violence Investigations. She is also a graduate of the Sherman Block Leadership Institute, Class 142.

Over her career she has served a number of various assignments such as a D.A.R.E. officer (Drug Abuse Resistance Education), field training officer (FTO), reserve officer coordinator and trainer, and youth council coordinator.

She has worked criminal investigations and presently supervises all criminal investigations as processed and handled by the detective. Along with these responsibilities, she is also the department field training officer coordinator, 290 (sex registrants) and is the liaison coordinator with the County Street Interdiction Team (SIT).

Lieutenant Burnett has also volunteered to represent the department with the Kern County Domestic Violence Law Enforcement Committee and in the City of Shafter Emergency Operations Center as the press information officer. 

Sergeant Lionel Lopez


Sergeant Lopez came to the City of Shafter Police Department in February 2000. Prior to joining the SPD, Sergeant Lopez served for four years as a deputy sheriff for Tulare County Sheriff’s Department and five years as a police officer for the City of Lindsay.

Sergeant Lopez began his law enforcement career as a Reserve Police Officer for the City of Lindsay in February of 1991 at the age of 20. In December of 1993, he completed the Tulare-Kings County Police Academy located in Visalia and went to work for the City of Lindsay as a regular full time police officer.

In March of 1996, Sergeant Lopez went to work for the Tulare County Sheriff's Department. As a deputy sheriff assigned to the Porterville Substation, his area of responsibility included, but was not limited to: the unincorporated areas of Porterville, Springville, Strathmore, Lindsay, Woodville, Ducor, Poplar, Terra Bella, Richgrove, and the Tule Indian Reservation.

Sergeant Lopez was promoted to the position of a senior officer in December of 2006, and then Sergeant in 2008. His duties have included; field training officer, watch commander, gang officer and is court certified as a gang expert and teaches about gangs when time permits.
Sergeant Lopez

Sergeant Randy Milligan


Sergeant Milligan was raised in a small town in Kern County. He became a Kern County Sheriff Reserve in 1999, and was hired as an extra help deputy sheriff shortly after. During the off season, as an extra help deputy sheriff, he worked as a Kern County Child Support Investigator and Housing Authority Investigator, assigned to investigations in the Shafter area. While working the Shafter area he realized how much Shafter reminded him of the town he was raised in with the presence of hometown and community values.


He was hired as a police officer with the City Of Shafter in June of 2003. He quickly volunteered for special assignments of traffic officer and police fleet manager. As a fleet manager he worked diligently to bring the fleet to a professional and functioning level. He soon realized that emergency vehicles were becoming more complex and that a tremendous amount of work was required to get these units service ready. In 2004, he began to standardize the fleet by converting the fleet units back to black and white as well as outfitting the fleet with consistent emergency equipment.
Sergeant Milligan
In 2004, he became the departments K-9 handler where he demonstrated how a highly dependable and devoted K-9 program should function. He worked with his partner Dak until Dak’s retirement in 2007.

He was selected as officer of the year in 2004 by his peers. He distinguished himself by receiving commendations from the Kern County and Denver Colorado District Attorney Prosecutors for his high quality of arrest and investigations. He has received numerous positive comments from his supervisory personnel regarding his high level of loyalty and dedication to the Shafter Police Department and other departmental personnel. He joined the long list of those officers who have distinguished themselves in the Shafter Police Department and the law enforcement profession.

In 2006, as he advanced in his career, he saw an opportunity to influence the future of the department and became a field training officer. In 2006, he was promoted to a senior patrol officer and in February of 2010 was again promoted to sergeant.


Sergeant Gustavo Olvera

Sergeant Gustavo “Gus” Olvera began his career in law enforcement in 1991, by joining the Kern County Sheriff’s Department Explorer Post #519.  In 1996, he was hired by the F.B.I. as a Linguist and assisted special agents with wire-tap investigations throughout the country.   In 1998, he became a Reserve Deputy Sheriff for the Kern County Sheriff’s Department and worked various assignments throughout northern Kern County.  In 1999, he was hired as an Investigator by the Housing Authority of the County of Kern to conduct investigations of narcotics, gang, fraud, and lease violations within government subsidized housing.   

Sergeant Olvera started his career with the Shafter Police Department in 2005, as a reserve police officer.  In 2006, the City of Shafter sponsored him as one of four cadets, for the first time, through the police academy.  He successfully completed the training and was hired as a full time police officer in November 2006.

Sergeant Olvera
During his tenure with the Shafter Police Department, he has served in the following assignments and ancillary duties; Reserve Police Officer; Dispatcher, Field Training Officer, Terrorism Liaison Officer, Task Force Officer with the F.B.I. Violent Crimes Gang Task Force, Narcotics, Shafter Police Officers Association member and President, Treasurer for the Police Activities League, Explorer Adviser, Fleet Coordinator, and Assistant Jail Manager.   In February 2010, he promoted to Senior Police Officer and in 2013 he promoted to Police Sergeant.  Sergeant Olvera holds a Bachelor of Science in Business Administration and an M.B.A.

Sergeant Chris Grider


Sergeant Chris Grider was promoted to sergeant in December, 2013. He previously was serving as the department detective responsible for investigation of major crimes, acts as the court liaison, works with the Alliance Against Family Violence, as well as other ancillary duties.

Sergeant Grider started his law enforcement career in the United States Air Force as a law enforcement specialist and rose to the rank of SSgt/E-5. He has served in Alaska, England, and Edwards Air Force base in California. He is a veteran of Operation Desert Storm while serving in Dharhan, Saudi Arabia. He has worked numerous specialized assignments throughout his career to include U.S. Secret Service support for Presidential and State Department personal security operations, Space Shuttle Recovery Team, Nuclear Weapons Security, Military Police Investigator, Police Training Instructor, and as a member of the Air Force Office of Special Investigations Joint Drug Enforcement Team.

After his military career he joined the Kern County Sheriff’s Department where he worked as an extra help deputy sheriff in positions of court guard, work release compliance deputy, and a substation patrolman.

Sergeant Grider was hired by the Shafter Police Department in 2002. He has attended a wide variety of training courses to include criminal investigations, traffic accident investigation, drug investigations, homicide investigations, and wiretap investigations, to name a few. He is a court certified drug and gang expert and recently attained accreditation as a geographic profiling analyst.
Animal Control Manager Nick RiddickRiddick
Animal Control Manager Nick Riddick was born and raised in Fresno, California. He attended the University of California, Riverside leaving for a supervisor position at a Fortune 500 Company. 

Life would lead him back to the beautiful San Joaquin Valley, however, and to the City of Shafter which he now calls home. Nick has been a resident in Kern County for nine years, where he found his calling in the Animal Control field. 

In November of 2009, he accepted a position as an Animal Control Officer for the County of Kern. He was selected as the Lead Officer in the newly revamped Public Education and Enforcement Team Program, or PEET.  This program consisted of public outreach to promote the importance of licensing and vaccinating pets as well as responsible pet ownership. 

With a successful tenure as the “PEET” Officer, Nick ventured into field services which entailed responding to a variety of animal related issues. It was not until he began responding to reports of Animal Cruelty and seeing firsthand the kinds of terror that can be inflicted upon animals that he realized he had a golden opportunity to effect change, hold people accountable for their actions, and save lives. He carries this creed to whatever situation life presents and is steadfast in upholding these values for the citizens of this community.

In 2013, Nick accepted the position of Animal Control Manager for the City of Shafter, bringing with him the experience and understanding of community involvement and participation. This has resulted in an increase adoption levels and rescue live release rates of animals, while steadily maintaining increased animal intake numbers and calls for service. 

Nick has a team of professionals and volunteers who are vigilant in impounding stray and marauding animals, but also dedicated to work toward lowering the annual euthanasia rate. This multi-pronged approach is accomplished partially with increased live release rates, carefully vetted rescue partners, and a thriving volunteer program.

In 2015, Officer Riddick was awarded the Officer of Year and continues to strive for the dedication to service the citizens of our community deserve.

Civilian Supervision Staff


Just as important as supervision over sworn personnel is the supervision over civilian staff. As we have with our police supervision staff, we have a great civilian supervision team as well. We'd like to take the time to introduce them to you as well.

Dispatch and Records Supervisor Lynn Yoshikawa  

Lynn Yoshikawa
positions over the years, starting off as a community services and animal control officer. Then in 1996 Lynn became a police dispatcher and began to learn everything she could about the paperwork aspects of the Police Department. In 1998 she was promoted to records / dispatch supervisor.

As the supervisor, Lynn oversees the dispatch operations and supervises the Shafter Police Department Dispatchers. Her records duties incorporate responsibility for handling all criminal paperwork for the department, including performing audits on all police reports for data entry accuracy, compiling statistics, and making required monthly reports to the California Department of Justice. She is also responsible for maintaining records on all Sex Registrants, Arson Registrants, Narcotics Registrants, and Concealed Weapons Permits. Her 20-year historical knowledge of the city and its resident’s make Lynn a valuable commodity for the organization.