Is it legal for me to post signs identifying someone a rapist?

Last week, a 17-yr-old boy d my 12-yr-old daughter. I live in Indiana and our state law says that it is still a crime even though he's a minor, too. There is a criminal investigation going on because there were other victims at other times, but meanwhile he is walking around free and clear, still going to his high school and I doubt his parents even know what's going on yet. I'm SO angry. I NEED to do something. I made up a bunch of color flyers with his picture on it that says his name and then says "d my 12-yr-old little girl". I'm thinking of going over to his high school tonite while it's dark and plastering the school and street lights with the flyers so he'll be an outcast at school (and hopefully get his *** kicked by one his peers). Since the allegation is true, it isn't libel. My understanding is that to be charged with "defamation of character", the allegations must also be false, so I think I'm safe legally to do this. Does anyone know? BY THE WAY- I'm not asking if I SHOULD do this...don't judge me because you'd be surprised at your level of anger if this happened to a little girl you love. I'm simply asking about the legality of it....Thanks