T.Ferrante of New Jersey!
Thanks to everyone who entered. The correct answer is: MORIRAI A MEZZANOTTE (in English: MIDNIGHT HORROR, MIDNIGHT KILLER, YOU'LL DIE AT MIDNIGHT, etc.), a giallo directed by the younger Bava, Lamberto. Mr. Ferrante also added the name of the poster artist, Enzo Sciotti. Thanks for the extra Monsterology tidbit, TF!