Examine the police role in criminal investigation and its constitutional discipline.

The police are the state's first-line agency of crime control and order maintenance. Goals: protection of life and property, preservation of peace, enforcement of law, and public service. Objectives (the operational ladder): crime prevention, crime detection and investigation, apprehension of offenders, evidence collection, victim assistance, traffic and public-order management. Functions (the classic triad): (i) law enforcement (the crime-response core); (ii) order maintenance (disputes, crowds, processions — the peace-keeping face without which the law's face fails); (iii) service (lost children, emergencies, escorts — the welfare face that builds the legitimacy on which intelligence depends). The goals' tension: crime control vs. due process (Unit 1.5) is the police's daily constitutional test — Art 20's arrest safeguards (grounds informed, counsel from arrest, production within 24 hours) and Art 22's torture bar bind every function.