$corpse->RemoveItem($slotID) issue

[c0ncrete]

Any suggestions as to why RemoveItem() might not work on an NPC corpse? I'm trying to delete the last item the NPC was manually given after spawning and having it killed using a line such as this one:

$corpse->RemoveItem($corpse->CountItems());

I'm currently using $corpse->Delete() to keep the item in question from being retrieved, but I'd like to be able to keep the original loot generated upon spawning.

NOTE:
I've looked in the source and nothing is really standing out to indicate I'm way off base in my understanding of how this function should work.