Comparative Analysis of Data Protection Laws and Digital Privacy in Criminal Investigations

Abstract

Digital criminal investigations increasingly depend on smartphones, cloud platforms, biometric repositories, location records, social networks, and algorithmic tools capable of processing large volumes of personal information. This expansion of investigative capability has created a difficult legal problem: privacy legislation must protect individuals from disproportionate surveillance without preventing authorities from obtaining legitimate digital evidence. The present study develops a comparative framework for examining this tension across the European Union, United Kingdom, United States, and India, with particular attention to developments between 2021 and 2026. A central research gap is identified in the limited integration of conventional comparative data-protection analysis with the operational consequences of artificial intelligence, automated evidence triage, biometric analytics, cross-border cloud access, and machine-supported investigative decision-making. The study therefore proposes the concept of an Investigative Privacy-Proportionality Framework (IPPF) for evaluating how different legal systems regulate necessity, purpose limitation, sensitive-data processing, automated decisions, transparency, accountability, and international data access.