Five Women for the Killer (1974)

Thriller about a reporter who comes home from an overseas assignment to find his baby in the hospital and his wife dead. The baby isn't his, the reporter learns from his doctor friend Lydia Franzi, as he is quite sterile. Reporter Giorgio and Lydia soon become lovers, and she narrowly escapes the brutal hands of the murderer (or murderers) who claims several other victims in shockingly violent fashion.