Ofcourse, There Was Poison

If there is a cup full of dried blood in this cabin, then you should not be surprised that there is also poison inside the house. Gum Turpentine is a kind of oil made of pine tree sap and if it is consumed it acts as a poison. Why could not the residents use normal oil? Why something that can also be used as a poison? Whoever was in here, were not usual, normal people.