The most common types of environmental crimes are the illegal dumping of waste materials and the falsifying of an organization's environmental records. In the investigation of such crimes, it is important to distinguish between civil and criminal environmental offenses. Criminal law involves action against an individual, and civil law pertains to action against companies that violate environmental laws. The role of law enforcement agencies regarding environmental crime can range from being responsive to citizen complaints to being proactive in detecting violations of environmental offenses. As a consultant in investigations that police believed required geological or soil analyses, Wilkerson always works under search warrant conditions. His work may involve the sampling of soil or surface water to determine whether it contains hazardous and petroleum waste that is evidence of illegal dumping. If evidence of illegal dumping is found, law enforcement officers may conduct stakeouts at strategic times to determine who is doing the dumping. Some investigative tools and techniques are aerial photographs, topographical maps, geological maps, and assessment of the risks to human health of a particular violation. This article also discusses types of tests for soil and groundwater, levels of contamination required to prompt a prosecution, environmental offenses associated with meth labs, and the future of environmental crime investigation.