OOC:
What do you do next? Clear rooms? Check out the other residents? Retreat and regroup and revisit the evidence you have so far? Do some research?
Perhaps this is obvious wisdom, I know you are all experienced players, but these types of investigations are a little different from more adventure-oriented games. You guys are on track. If you feel like you're at a dead end in terms of actions you can take, get out there and get more intel.