The letter "h" was added to the name "Ward" just before the film was released when an Italian woman named Mrs. Ward threatened legal action over the original title potentially damaging her good name.
The film was refused a UK cinema certificate in 1971 but later passed uncut for DVD in 2011.
The film was originally released under the title Blade of the Ripper in the United States. It was also released under the alternate titles Next! and The Next Victim.
Jean (Ivan Rassimov) sends Julie (Edwige Fenech) flowers with a note that says, "Now I know you're trying to get away from me, but your vice is a room locked from the inside and only I have the key." A year later, Sergio Martino would direct "Your Vice is a Locked Room and Only I Have the Key" which would also star Fenech and Rassimov.
Italian censorship visa #57415 delivered on 12/23/1970.