Sleep Tight (2011)

César works as a doorman in a Barcelona apartment building. He goes about his day to day work mainly unnoticed by the residents of the building, but he pays close attention to them. He knows all the intimate details of their lives, everything about them, specially one of them. In Clara he has found the perfect target, and he will go to extreme lengths to make her life miserable. But César is starting to get a bit too cocky, and soon his carefully thought out plans will start to unravel... Luckily for him, he has one last ace up his sleeve.