How to make an end crystal drop an item when destroyed?

Is there any way to make an end crystal drop an item when destroyed using a procedure? I've tried a bunch of different ways, but I haven't found one that's worked. The main problem I'm having is that I can't seem to find a way to detect when an end crystal is actually destroyed. I've got detecting if the target entity is an end crystal and spawning the item down, I just can't find a global trigger that would work. Entity attacked, entity dies, and entity about to grief world don't work. Is there a way to detect it?