I Am Not a Serial Killer (2016)
A creature of unknown origin falls in love with a human woman. To stay by her side he kills people and steals their body parts so that he can maintain his human form. Old age see’s them living in a Minnesota town with young John as a helpful neighbor. Essentially though, John’s observations of the recent murders in their town, combined with his understanding of a killers mentality, lead him to uncover his elderly neighbors strange secret.