Short horror stories

Knock knock

  About a year ago I moved into a new apartment. It wasn't anything special, but it was nice to have a place of my own. I was sick of being the guy who still lived wiry his mom.
  When I first moved in I felt kind of lonely and out of place. I was living by myself and I knew basically no one. Until one day a very beautiful girl caught my eye. She had long, brown hair and beautiful green eyes. She was just so perfect and it made me feel nervous that a girl like her was moving into a place like this. I became very excited when I found out that she was moving into the apartment right next to mine.
I was usually very nervous around girls but I really wanted this girl to be mine. Since her apartment was right next to mine, I started by knocking on her wall and talking to her through it. She had such a soft and kind voice. She was absolutely perfect.
  Nearly everyday we would do this. I would knock on the wall and if she knocked back then I knew she was there. Sometimes we would even talk for hours. Every time I saw her in the lobby, we would always give each other a smile but never actually talk to each other. We seemed comfortable where we were.
  We continued this until one dat tragedy struck. One night when I was out with a couple of friends at a bar a man broke into her apartment and robbed her and murdered her. I felt absolutely devastated. I felt like if I was there, maybe I would've been able to save her.
  Once again I felt lonely in my apartment. I lost the one person that I truly cared about. I thought about her everyday.
  One day when I missed her desperately, I decided to knock on the wall, just like the good old times. I felt a rush of fear go throughout my body when I heard a knock knock from the other side....