Deep Red (1975)

An English pianist living in Rome witnesses the brutal murder of his psychic neighbor. With the help of a tenacious young reporter, he tries to discover the killer using very unconventional methods. The two are soon drawn into a shocking web of dementia and violence.

Deep Red was on the Section 3 Nasties List and was liable for seizure and forfeiture by the police. Passed with 11s of cuts in 1993. The extended version was passed uncut in 2010.