Wiktionary
n. murder accompanied by mutilation, often of a sexual nature
Wikipedia
A lust murder is a homicide in which the offender searches for erotic satisfaction by killing someone. Lust murder is synonymous with the paraphilic term erotophonophilia, which is sexual arousal or gratification contingent on the death of a human being. The phrase "lust killing" stems from the original work of Richard von Krafft-Ebing in his 1898 discussion of sadistic homicides. Commonly, this type of crime is manifested either by murder during sexual activity, by mutilating the sexual organs or areas of the victim's body, or by murder and mutilation. The mutilation of the victim may include evisceration, displacement of the sexual organs, or both. The mutilation usually takes place postmortem. Although the killing sequence may include an act of sexual intercourse, sexual intercourse does not always occur, and other types of sexual acts may be part of the homicide.
Usage examples of "lust murder".
The homicide falls under the heading of lust murder, as is clearly indicated by the torture to which the victim was subjected antemortem, but I would be hesitant to categorize this UNSUB as being in the same sort of crazed frenzy as we saw in Jack the Ripper’.
One lust murder don't look much different from another no matter who's committed it unless the squirrel's into drinking blood or barbecuing people on spits - and this squirrel we're dealing with ain't a Lucas.