There are speculations that satanic rituals were conducted at the Tauton State Hospital!

The Taunton State Hospital located in Taunton, Massachusetts was built in 1854 as a psychiatric hospital. The hospital was home to Jane Toppan, a former nurse who killed at least 31 people. However, it’s suspected that the medical staff was worse than she was.

There are rumors that some of the doctors and nurses would take patients into the basement and use them to conduct satanic rituals. In later years, both patients and doctors reported to feeling a tremendous sense of unease when even approaching the door of the basement. Some reported to seeing a “shadow man” who would crawl on the walls and just stare at the patients.

(Source)