This story happened to me when I was 15 but it didn't seem to be evil, it seemed like it just wanted to tell me that it was there and that it was just visiting. About 2 years ago I was home alone (I have a graveyard in the backyard.) I was waken up to this loud bang coming from my room (I was on the couch - one storey house). When I got up and investigated my room, I found nothing wrong so I was thinking the house shifted but then when I started to walk out, I heard my name and I turned around and I saw this soldier (in my graveyard we have soldiers from WW2 and the revolutionary war), but then when I blinked and he was gone. So I just figured I was dreaming or just crazy.
But then the next night I was laying in my bed and I smelled a gun-smoke kind of smell and then it vanished and I got up and went and told my mom and she just blew it off like "it's not true your just imagining it".
But then about 2 weeks after I told her, I was with her and we were sitting in the kitchen just talking and I heard the noise again and this time, she kind of believed me and said she was sorry about not believing me when I told her the first time. So 2 years later this spirit hasn't come back, so I figured he was just visiting.