The Killer is Not Alone / El asesino no está solo (1975)

Affected by traumatic events suffered in childhood, a damaged young man becomes a killer and decides to murder women who sexually excite him. It's a psychological thriller with some slasher violence. It's more interested in setting an atmosphere that glorifying in bloody mayhem though. Overall, it works pretty well. It's a stylish film and the Spanish feel to it adds a lot to the aesthetic.