Police Officer's Power to Investigate Cognizable Cases

Explanation

Section 156 defines the scope and authority of police investigation. Section 156(1) is the investigation power — police can investigate cognizable offences autonomously, without any judicial order or permission. This reflects the constitutional design where investigation and prosecution are police/state functions while adjudication is a judicial function. Section 156(3) is one of the most litigated provisions in all of criminal procedure — it allows a Magistrate to direct police to investigate a case. In practice, Section 156(3) petitions are filed when: (a) police refuse to register FIR; (b) police register FIR but do not investigate; or (c) complainants want judicial oversight of a potentially compromised investigation. The Magistrate under Section 156(3) can direct 'investigation' — which includes registering FIR if not already done. The Supreme Court in Mohd. Yousuf v. Afaq Jahan (2006) confirmed that a Magistrate directing investigation under Section 156(3) implicitly includes the direction to register an FIR. However, the Magistrate cannot direct the police to register a specific case — only to investigate — leaving the actual investigation conduct to police discretion.