The Fifth Commandment (2012)

Original title: El quinto mandamiento

Víctor, a psychopath, loves carving crosses onto women post-mortem, blames paedophile priest and mother-in-denial for his behaviour, falls in love with one of his intended victims and decides to give up his adopted lifestyle. An alcoholic detective (he’s mourning his sister’s passing), eventually tracks down Víctor, and manages to break his habit with the bottle.