Arrow - Spoilers galore

brock, Ra's already made himself a suspect at the end of episode 4 when he told a returning Nyssa that he's glad Sara died, since she never embraced being apart of the League of Assassins anyway. I do think Nyssa's remorse for Sara was genuine and obviously if her father did set her up by sending an assassin to kill her on a bogus mission, he'll have hell to pay if his daughter finds out, and in several of comic story lines, Nyssa hated her father bitterly years after WWII for collaborating with Nazis' Final Solution and in fact spent time as a prisoner at Auschwitz.

Also, what if Merlyn really isn't on League of Shadows hit list anymore and was the one who killed Sara? And maybe he or one of his associates killed her on Ra's orders but tried making it look like Arrow or one of his associates did it to play on Nyssa's grief that she would go after Arrow out of revenge? If he didn't really die at the end of Season 1, Ra's would've found out pretty quickly, perhaps he and certain members of League came to some sort of secret truce to take care of a mutual enemy in Oliver Queen and later on, the Flash if he got involved.