Police brutality in custody is a direct challenge to constitutional government because the state assumes control over the body, movement and immediate safety of the detained person. This paper examines custodial violence in India through a doctrinal and socio-legal review of constitutional guarantees, criminal-procedure safeguards, judicial decisions and accountability institutions. It argues that Indian law contains substantial protections under Articles 14, 20, 21 and 22 of the Constitution, supported by the Bharatiya Nagarik Suraksha Sanhita, 2023, the Protection of Human Rights Act, 1993 and leading decisions such as D.K. Basu v. State of West Bengal, Joginder Kumar v. State of Uttar Pradesh and Nilabati Behera v. State of Orissa. Nevertheless, the preventive value of these rules is weakened by informal detention, poor documentation, coercive interrogation, delayed medical examination, weak complaint mechanisms, political interference and institutional control over evidence. The paper proposes a rights-respecting custody framework based on verifiable arrest records, prompt legal and family access, independent medical documentation, reliable audio-visual recording, meaningful judicial scrutiny, independent investigation and transparent publication of outcomes. It concludes that police effectiveness and human rights are mutually reinforcing because evidence-based investigation and accountable custody improve both legitimacy and the quality of criminal justice.