ORIGINAL: Sanguinius

Oh and slow you got the question wrong. It's a funeral that she sees the guy at not a wedding. You can't logically make the jump if she saw him at a wedding. Then she'd have to force someone else to get married. But if she sees him at a funeral then kills her sister she figures he'll be at the next funeral. (The REALLY scary part is I actually came up with QUITE a few ideas and theories on this and all of them just as scary LOL And the sick part of this whole question is the fact that if this guy was at the first wedding/funeral then he;s OBVIOUSLY family... INCEST...)