James Christopher Lawrence’s review published on Letterboxd :
Considered by many to be the first Gialli, this is Bava all over. Bava deserves to be put on a pedestal for this film due to the influence it’s had on some of cinemas greatest modern directors. It’s all there, the red herrings, the masked gloved killer, the dumbfounded police and many beautiful victims. For a film made in 1964 it is pretty violent, but remember this is 1964.
Of course there are much better Giallo’s but for a film that set the pace it’s spot on. I would love to see a better print as I did struggle during the night sequences.