5 yr old with bad thoughts

Hello,
My 5 yr old daughter tells me her brain is thinking bad thoughts. (one that really scared me is " my brain is thinking of killing grandma"). She says she doesnt know why her brain is thinking that and knows its not right. She says she would never hurt grandma (she is very close to her). She asked me to tell her brain to make the bad thoughts go away. Should i have her checked out? How can i help her?  Im scared to not do anything about it and 20 years from now she will be some psycho killer! Please Help!