Did You Know?
When interviewed on set in 1977, director Pier Carpi
angrily denied that his screenplay was inspired by The Exorcist
(1973) and pointed out to the interviewer that he merely adapted his own novel "Un ombra nell'ombra" which he claimed to have written in the sixties but which, in fact, was published first in 1974. However, it is assumed that Carpi's original cut of the movie was considered too much unlike "The Exorcist" by the producers who thus ordered extensive re-cutting and re-shoots. See more