La morte non ha sesso (1968) by Massimo Dallamano
aka: A black veil for Lisa

Being in the position of a police inspector obviously helps to detect and resolve a lot of naughty things even though not all investigations might be equally satisfying in the end. Inspector Franz Bulov (John Mills) has to learn this bitter lesson, as, despite his obsessive but definitely not unfounded private control patrols, Madame Bulov, aka Lisa (Luciana Palluzzi), leads a jolly secret double life behind his back and opens the door not only to her husband. A successful detention of the main suspect in his recent case suddenly delivers him a completely new perspective, … but not only for him, of course.
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Enigma Rosso (1978) by Alberto Negrin
aka: Rings of Fear

Inspector Gianni di Salvo (Fabio Testi) has to slip over several murmurs before he can close his delicate case of murders in and around a rich girls residence school. While he is making unrequested waves in the dormitories of the staff and the girls, the murderer kills and kills again, suspiciously always exactly one step ahead in the inspector’s investigation line. How could the killer know of his plans and who writes in the name of Nemesis? Some clues don’t seem to match up.
seen at: pickledfeet private videothek