Accidents happen.
I was walking around a park with my top hat on and a black suit, so I looked very civilised. This lady walked up to me and asked if I wanted to play frisbee with her kid. I agreed, and we threw a frisbee back and forth for a while until she was out of sight (I think she said she needed to make a phone call or something). Then I pretended to drop the frisbee on the ground by accident, and I opened up my suitcase and pulled out a circular saw. I then threw it at the kid and it decapitated him. I was gone before his mother came back. Or she could have been an aunt.