Sexual assaults, other sexual victimizations, and deaths of subjects caused by their performance of risky autoerotic scenarios result from behaviors that stem from mental fantasies of sexual scenarios that in aberrant form involve sexual aggression, domination, power, and control. These fantasies are fueled and reinforced through the use of sadistic pornographic materials and may be acted out with consensual sexual partners; crimes occur when the fantasies lead to victimizing sexual acts that violate criminal laws. Detectives involved in the investigation of sex-related homicides and deaths should give priority to the role of fantasy in sex-related homicides and accidental deaths due to sexual asphyxia. Search warrant applications in these types of cases should reference any photographs, records, writings, videotapes, computer content, and other materials that can document the types and strength of sexual fantasies harbored by the subject of the investigation. Such material can serve as evidence of the suspect's sexual fantasies and their logical link to the crime at issue.