David J. Derksen is the Chief Investigator of the Bureau of Investigations and reports directly to the District Attorney. He is responsible for the safety and security of the District Attorney and all District Attorney Personnel. He is also responsible for planning, coordinating and supervising the activities of District Attorney Investigators assigned to the Bureau. District Attorney Investigators are statutory full-time peace officers who conduct investigations on behalf of the District Attorney. They provide quality and timely investigative support for the prosecutorial functions of the San Joaquin County District Attorney's Office to enhance public safety. They collaborate with Deputy District Attorneys in the vigorous enforcement of criminal and civil laws.
The Bureau routinely uses investigative methods and techniques to gather and evaluate evidence, and to obtain information through interviews and interrogations. The Bureau conducts investigations resulting in the apprehension and prosecution of persons suspected of committing criminal offenses. The core units of the Bureau are criminal investigations which include Vertical Prosecution Crimes: Homicide and Gangs, Child Abuse Sexual Assault (CASA), Domestic Violence, Sexually Violent Predators, Child Abduction. An additional core unit referenced as the Quality of Life Division encompasses: Public Corruption and Integrity, Public Assistance and IHSS Fraud, Workers’ Compensation and Auto Insurance Fraud, Consumer and Environmental Crimes, Real Estate Fraud, and Elder Abuse. The Bureau also investigates all Officer Involved Critical Incidents in San Joaquin County.
Chief Derksen grew up in Stockton and is a second generation law enforcement officer with over 30 years of experience in San Joaquin County as a peace officer. Chief Derksen joined the Bureau of Investigations in 2007, after serving 22 years with the San Joaquin County Sheriff’s Department. He has an extensive background in working complex investigations. In 2014, he was promoted to Lieutenant and has supervised all investigative units of the Bureau. He is truly vested in this community to make it a better place for all to live and thrive, and to help and protect the rights of the victims and witnesses we serve.
“It is an honor and a privilege to serve the people of the State of California.”