If you want to delete the corpse after it dies, you should check out this quest I posted here:
http://www.eqemulator.net/forums/showthread.php?t=25927
You will still need a way to get the class that got the kill, but one you do, you can replace the IsEmpty check in my script to check for the class instead. Might be useful.
So, are you trying to ensure that a certain class is soloing this NPC, or the only thing that matters is if the right class gets the killing blow? If you are trying to make sure that the right class is the only one killing it, you could probably just have it check everyone on the hate list and check their class and if they aren't the right one it depops.