A detective is a specialized investigator, usually within a law enforcement agency, who solves crimes by collecting physical evidence, interviewing witnesses, and searching records to arrest and convict offenders. Recruitment paths vary: some detectives pass written exams after serving as uniformed officers, while others join directly as college graduates, and they are typically organized into squads dedicated to specific crimes like homicide, fraud, or narcotics. In Commonwealth forces, they hold ranks such as Detective Constable (DC) or Detective Sergeant (DS), distinguishing their investigative duties. Outside the police, private detectives—often called "private eyes" or "PIs"—work independently, though their evidence may not always hold up in court, as is the case in Portugal. Additionally, citizen detectives are unpaid amateurs who help solve crimes for personal justice, a love of law and order, or pure recreation, often assisting police through tips or neighborhood watch groups.