Obscure the Malice
In this ritual, the caster pours her own vitae into a corpse's wound. The blood scabs over and the wound "heals," during the course of the ritual. This ritual can not be used to heal the living or undead, though it can conceal evidence of feeding or other physical violence on a corpse.
System: The player's successes on the activation roll determine the visibility of the scar. One success indicates a very visible wound (that nonetheless must have healed before the victim suffered whatever trauma killed him...) while five successes heals the wound flawlessly postmortem. this ritual works only for wounds - poisons, drowning, etc. will still be evident with a full autopsy, though such results may prove misleading without other telltale marks.