Hell's Heart (2015)

Martin Cole, a lonely ten-year-old boy becomes enamored with Lisa, a woman who lives across the hall with her seemingly perfect family. One evening, Martin witnesses her brutal murder, and his life changes forever. Decades later, Martin is engaged to Lisa's daughter. But as the wedding draws closer, his behavior grows increasingly bizarre, as if something is taking control of his mind and body. Now, either in the grip of a demonic possession, or descending into madness, Martin is convinced that the invading spirit is Lisa herself, opening old painful wounds for her family and rekindling his first love.