Ok, I think this is more for killing several creatures with the same death variable. (like reevors rat quest)
But still thanks for pointing that out, might need it later!
0x4051 Dead(S:Name*) Returns only true if the creature with the specified script name has its death variable set to 1. Not every form of death sets this, but most do. So it's an almost complete test for death. The creature must have existed for this to be true. Note that SPRITE_IS_DEAD variables are not set if the creaure is killed by a neutral creature.
For my purposes it doesn't matter wether Mulahey gets killed by neutral creatures or the NPCs group. Is there anything else?