OOC:
This is an extended action. Your combined successes count as research. With 6 successes in your investigations, you learn the following.
Together, with proper lighting and the benefit of your arcane senses and talents, you examine the cellar, the sacrifice, and the remains.
Some mages have recorded incidences of strange creatures referred to as Flesh Intruders that take up residence within the body of a victim. They are Abyssal creatures that quickly begin transforming the internal organs of a victim into strange, specialized organs for its own use, and breaking everything else within down into a vile, acidic mess that it can use as a weapon.
This creature was only partially formed, and after being summoned into the body of the sacrifice, had likely emerged, and then retreated to the cellar to hide while it finished
becoming. The second body, the one hanging in the front room, was probably the sacrifice, the price for the intruder to break through from beyond the qlippothic spheres. Whose body the intruder had inhabited, is unknown.