Attrition of rape cases is highest during the police investigation. As annually increasing reports of rape contrast with low conviction rates, this research determines which features of an investigation impact the likelihood of attrition. Cox Proportional Hazards Analysis of 620 rape cases highlights where and when attrition is greatest, in order to improve each stage of the investigation. The analysis found initial attendance by uniformed officers and conducting an interview significantly decreased attrition likelihood. Alternatively, matching the gender of officer to victim significantly increased likelihood. Moreover, victim-perpetrator relationship significantly impacted case length.