Cursed (2005)

Answer: I assumed it was Jake based on what transpired in the previous scene and his face was the last one shown before the elevator door closed. Jake told Ellie he didn't want to lose her, they had something "special", and asked if she would bear with him until he overcame some difficulties. Jake saw Jenny as a pest as well as someone who could ruin his still-developing (blossoming) relationship with Ellie. Jenny confronted Jake about not calling Becky anymore. Jake responded that he put himself "off the market" (was no longer available because he was pursuing Ellie), to which Jenny responded that she was "bummed" (disappointed because Jake was not free to pursue her). Jenny also put her hand over Jake's shoulder, which Jake did not like because he was not interested in her and was afraid that Ellie would see (which she may have). To top it off, Jenny kept following Jake around the room when he was talking to other people. Jenny was clingy and persistent - so had to be eliminated.

KeyZOid

Chosen answer: Joanine made a crack saying "I guess there is no real way to have safe sex with a werewolf. Joanine dated Jake before Ellie, hence how she became a werewolf before Ellie and Jimmy. In fact it was Joanie who made Ellie and Jimmy werewolves because she stated she was killing the other girls Jake was interested in.