Nightwalking (2008)

A woman takes a shortcut and is followed by a stranger. She is scared and is thinking whether she should run or not. Out of the blue, she decides to turn around and she sees nothing but a cell phone on the floor. In flashback, we see the stranger embarrassed for the reaction of the woman. He is aware that she believes that he might be a rapist following her, and he decides to call his mother to talk loudly on the phone and calm down the woman. However, something happens and the stranger vanishes.