Okay, I've got this idea for a novel... I won't divulge too much, but basically, recommendation-wise, I need someone to help me come up with a motive to kill. This isn't just a normal murder, but an assassination. Still, nothing to bad there; the thing is, the assassin is assassinating his sister. Now, he's following orders... but even so, what would bring someone to kill one's own sister? My problem is that I can't come up with something that she did that is worthy of an assassination. Recommendations are appreciated.