Helpfile:

Corpseguard is an option you can toggle on and off (see help TOGGLES) that allows you to automatically guard a corpse from lower ranking looters. This is only applicable to PC corpes that you create, that is to say you have to be the one to strike the killing blow. If enabled, the killer will have a chance to stop other players, that are underneath his PK range, that he can see, from taking items from the corpse. While a corpse is being guarded, low-ranking looters cannot use "get all" commands on the corpse. If the killer leaves the room or engages in combat, he will stop guarding the corpse and cannot start again.