They found that peer-adult juvenile sex offenders more often showed aggressive or violent behavior in their commission of their crimes than juvenile sex offenders who targeted children younger than themselves. Over 25 percent demonstrated a moderate-to-high level of aggression, and nearly 10 percent of victims required extensive hospitalization or died as a result of their injuries. Interaction between three variables predicted higher levels of aggression and violence--sex of the victim, age of the victim, and degree of victim resistance. In general, juvenile sex offenders used higher levels of violence against victims who were physically capable of defending themselves and who resisted. Seven juvenile sex offenders who murdered their victims ranged in age from 14 to 17 years. Victims ranged in age from 9 to 81 years. Juvenile sex offenders who targeted peers or adults often committed sexual assault in conjunction with another crime. In two cases, juvenile sex offenders intentionally tortured their victims. In three cases, juvenile sex offenders took valuable items from the victim or from the victim's home. The sexual assault included apparent penis-anal rape, penis-vaginal rape, penetration with a foreign object, and cunnilingus. Methods used by juvenile sex offenders to commit their crimes are examined, and case studies are included. Additional research on sexual violence is recommended. 8 endnotes and 1 photograph