The Professional Standards Bureau ("PSB") is a multi-tasked unit. Its primary responsibility is the investigation and prosecution of all police criminal misconduct in Essex County. Additionally, it serves as the internal affairs unit of the Essex County Prosecutor's Office, as well as the county's Bias Crimes Unit. PSB also monitors police pursuits in Essex County and maintains standards for their use, so as to help limit their danger to the public and yet maintain their use in appropriate circumstances for criminal apprehension. The Bureau provides training at the Essex County Police Academy and also provides individualized training in Internal Affairs at municipal departments. The Bureau has installed and instructed municipal agencies in the use and operation of the Random 2000 Drug Testing Computer Programs used in urinalysis testing of police officers. This service has also been rendered to municipalities outside of Essex County.

As part of his ongoing program to improve services to the citizens of Essex County, former Acting Prosecutor Donald C. Campolo made significant improvements in the area of internal affairs investigations. In 2000, he reorganized the chain of command within the Prosecutor's Office to have the internal affairs unit, then named "Citizens Complaint Bureau," report directly to him. This very positive change makes possible a more efficient disposition of cases. In May of 2001, the Citizens Complaint Bureau was renamed the "Professional Standards Bureau" and its role was expanded.

The Professional Standards Bureau consists of two branches. The investigative branch is manned by a captain, a lieutenant and four detectives. The prosecution branch is assigned two assistant prosecutors. One clerical staff member oversees all office operations and manages the records system. PSB functions as is a "vertical prosecution" unit. This means that all law enforcement criminal cases are exclusively handled by the unit from inception to trial. When the unit receives an allegation of criminal conduct committed by a sworn law enforcement officer, it initiates an investigation. Where applicable, a grand jury presentment may be necessary. If an indictment is returned, this unit is responsible for the case through a trial or plea agreement. Internal responsibilities include, but are not limited to, random drug screening, investigation of violations of rules and regulations, risk analysis management, and integrity testing.

In 2001, the Essex County Prosecutor's Office was made responsible for the implementation of the Critical Incident Response Team. All members of the Professional Standards Bureau participate in this innovative program and respond to critical incidents such as police shootings or pursuits involving injury or death and any other incident deemed critical by the Prosecutor. The unit responds 24 hours a day, seven days a week.