Child sexual abuse is a complex problem that requires the efforts and coordination of many agencies and disciplines. No one agency or discipline has the personnel, resources, training, skills, or legal mandate to deal effectively with every aspect of child maltreatment. The law enforcement perspective focuses on criminal activity and legally defensible fact-finding; therefore, the process must feature the collection and analysis of admissible evidence regarding what happened. It is important that in conducting interviews investigators be both aware of and in control of their own feelings and beliefs about victims and offenders in child sexual abuse cases. An officer who gets too emotionally involved in a case is more likely to make mistakes and errors in judgment. Any law enforcement officer assigned to the investigation of a case of child sexual abuse should be a volunteer, even if reluctant at first, who has been carefully selected and trained in this highly specialized work. One section of the chapter provides guidance to the law enforcement investigator in interviewing the child victim. Among the issues discussed in this regard are the disclosure continuum, establishing rapport and clarifying terms, videotaping, and general rules and cautions. Another major section of the chapter addresses issues in the assessment and evaluation of a child sexual abuse report. Attention is given to a determination of the accuracy of a victim's allegation. Among the investigative approaches reviewed are the corroboration of allegations of child sexual abuse, the documentation of behavioral symptoms of sexual abuse, the documentation of patterns of behavior, the identification of adult witnesses and suspects, medical evidence, the identification of other possible victims, search warrants, physical evidence, child pornography and child erotica, computer evidence, consensual monitoring, subject confessions, surveillance, creative prosecution, a proactive approach, and the establishment of communication with parents. A listing of 10 basic publications for investigators of suspected child sexual abuse and 9 references