The fact that Reverend Parris has discovered young girls dancing in the forest while Tituba speaks in her native language over a boiling cauldron of soup, which has a frog inside of it, is a reason to suspect that the devil has invaded Salem. It is clear that the girls are dabbling in the dark arts and it is even more concerning that Abigail is drinking chicken blood to put a curse on Elizabeth Proctor. It is also revealed that Ann Putnam sent her daughter, Ruth, to persuade Tituba to conjure the spirits of her dead children, which is another piece of evidence that suggests the devil has invaded Salem. The mysterious illnesses of Betty Parris and Ruth Putnam are also reasons for concern regarding the devil's presence. The false testimonies from Abigail and the others fuel the witchcraft hysteria and Abigail's accusation that Elizabeth sent her spirit to kill her is another piece of evidence that suggests the devil has invaded Salem.