I may be wrong but maybe the Haitian, if he was the one who stabbed her would make some sense because Dominicans won't usually kill a foreigner to just rob 'em. I would think personally that it would cause too much trouble to kill a foreigner because the "heat" would be on my tuchas like spit on the pavement, lickety split. Dominicans still appreciate that foreigners are kinda "hands off" because you can always rob them easier cuz they are disoriented and less on guard since they are relaxing, drunk, high or in large groups which would help or hinder a potential domino crook/thief.
The Haitian especially if he was a newcomer, would not be aware/conscious (or maybe he is that much of moron/dumbass) of the fact that you don't kill a tourist.
LC
I like to think the same way. There is a lot of crack and cheap street level drugs throughout the island though. When you have crazed, poverty stricken addicts involved there is no logic.