According to a 2006 study by Lisa L. Sample "Findings indicate that sex offenders do not frequently commit murder, nor do they commit homicide at higher rates than other types of offenders."
Study: An Examination of the Degree to Which Sex Offenders Kill
It seems clear that most of our current sex offender policies and those being proposed for the future are the result of sexually related homicides against children committed by previously convicted sex offenders. Given the enactment of these laws, one implicit legislative assumption emerges: that many, if not most, sex offenders go on to kill. This study explores the assumption that sex offenders often kill their victims. Specifically, criminal history information from Illinois from 1990 to 1997 is analyzed to examine the degree to which sex offenders are charged with murder in conjunction with a sex crime and the likelihood of arrested sex offenders experiencing a future arrest for homicide. These results are compared to those found for other types of nonsexual offenders. Findings indicate that sex offenders do not frequently commit murder, nor do they commit homicide at higher rates than other types of offenders.