Why do i have evil toughts ?

I have toughts of harming others in bad ways.. Even the ones i love. Like mi brother or i even had a tought of abusing and killing mi 5 old month baby cousin. Wich i love so much. I dont express my tought physically nor am i messed up in the head. Actuly im betetr then average. Im a state champion im very athletic im physically gifted ( or so iv been toled) but the things i think or far from mi actual nature. I have never been around violence. Im 15 and i think its because of the thi gs i watch and read. I do li,e horror films and i read the news alot and im pretty imformed to whats going on in this world.. Wich we all now, its a crazy world... Any thoughts?