I PERSONALLY BELIEVE ALL humans are bothered by demonic spirits(tempted-mind)but how demons come in...................
After a long stay at the Hospital, she begins to see devilish grimaces during her daily praying. In the fall of 1970 Anneliese returned to school, and while other girls live the freedom of the 70s, she starts believing she is possessed. She can't find another reason for the grimaces, nothing makes sense. Now, voices are following her, saying that Anneliese will "stew in hell" and her depression gets stronger and stronger. Anneliese doesn't see any reason for the meetings at the Doctors, they don't bring any relief. Just once does she tell a doctor about the "demons," which are now giving her orders. But the gap between known medicine and Catholic Ideology is too big, for her problems to be considered.
The Story of 'Emily Rose' - RopeofSilicon.com
In 1949 Robbie began to hear strange scratching sounds between the walls. His parents then called an exterminator but the noises just became worse. Then Robbie started to hear footsteps in the hall and was continually attacked by an unseen being. His bed began to shake so hard that he could not even sleep at night. When he tried to hold on to the sheets he was thrown to the floor with the sheets still clenched in his hands. When Robbie's parents couldn't take it anymore they contacted a Lutheran minister by the name of Luther Schulze. The Reverend took Robbie to spend the night at his house to determine if the Doe residence was haunted or if Robbie was actually possessed. Several minutes after Robbie went to bed the strange occurrences started again. The bed shook violently and the strange scratching sounds could be heard between the walls. When Reverend Schulze tried to make a bed for Robbie on the floor, the blankets and sheets moved across the room and under the bed.
The St. Louis Exorcism