Gosh I'm sorry, I completely missed this, April has been a Month. I have no time constraints (if you're even still interested after how much time has gone by), and if you don't want to play it, I'll still let you know what they would discover, which is:

in the cave, they will note that the blood pool is large enough to constitute a deadly loss of blood, and if they're experienced guessing the age of dried blood (Shen Wei is), that it seems to be dated to the time the cave began making people ill