CID stands for "Criminal Investigation Department," a specialized unit within law enforcement agencies responsible for investigating serious crimes. This department typically handles cases such as homicides, robberies, and sexual offenses. CID officers, often called detectives, gather evidence, interview witnesses, and work to solve complex criminal cases. In many countries, the CID operates under the umbrella of the police force but may have its own distinct structure and procedures. The department plays a crucial role in maintaining public safety and ensuring justice by thoroughly investigating crimes and bringing offenders to trial.