13 Steps Down (2012)

Mix Cellini is a young man with a disturbed past. He now rents the top floor of a dilapidated Notting Hill residence, in which a lonely mid-70s spinster lives. Two obsessions in Mix's life are supermodel Nerissa Nash, who he adores and stalks, and infamous serial killer John Reginald Christie, who Mix studies every chance he gets. Mix treads a fine line between reality and fantasy, and his obsessions collide when he unleashes long pent-up violence after his part-time girlfriend criticises his beloved Nerissa.