Operational practices between forensic science and environmental crime investigation make up ecological crime scene investigation (ECSI), which unites multiple disciplines to document and identify ecosystem violations for prosecution. These environmental offenses include the illicit disposal of hazardous substances along with forest clearance and protected animal poaching and trafficking, discharge of pollutant and emerging contaminats into air, water, and earth surface (soil) aside from leaving behind intricate physical evidence. Moreover, reconstruction of ecological crimes and tracking of their sources requires integration between forensic ecology, environmental forensics, forensic toxicology, and criminal justice principles and techniques through ECSI. Environmental forensic scientist detect identify and quantify pollutants, as well as emerging contaminants while tracing their sources through techniques, which include water and soil collection as well as satellite analysis and DNA identification and chemical substance tracing. Ecological investigations handle harmed ecosystems and species using specialized techniques and legal frameworks because they do not solely conduct investigations on human victims like traditional forensics do. The ECSI studies extended harm resulting from damage to the environment that causes damage to biodiversity and impacts human health and climate systems. The advanced scale of environmental crimes requires ECSI to serve multiple functions that advance both environmental protection and fairness. Law enforcement depends on this field, together with policy development and public awareness, because it translates intricate ecological harm into evidence for legal proceedings. Additionally, ECSI maintains its rising importance because societies worldwide are focusing on safeguarding environmental integrity. This chapter also supports United Nations Sustainable Development Goals; Climate action (SDG 13), Life on land (SDG 15), Life Below Water (SDG 14), Peace, Justice and Strong Institutions (SDG 16).