I Know I've Said It Before, but the Maternal Instincts...

I know I have mentioned this topic before, but it has surfaced again and has me beside myself. My son has been accused of being mean to another child, who is younger than him and smaller in size. My son is a good kid and spends a lot of time with younger kids and helps look after them, but this one kid has a history of being "difficult". He is a tattle-tale and whines to get his way. They have blamed my son for doing mean things to him. My son ends up in tears and pleading with me that he did not do those things. I feel bad because I can tell, in my heart, that he is telling me the honest truth that he did NOT do this stuff, but other kids are saying different (then again, what boy wants to get in trouble when there are 20 others who make good scape goats?) I have gone through the emotions of being angry, frustrated, hurt, confused, betrayed, lied to, and upset. I am probably taking it worse than him because my Maternal Instinct is kicking in... which is what is truly pissing me off!!! I guess it's my saying... you can mess with me and I will defend myself, but DO NOT mess with my mom or my son... then you're treading on thin ice and have to mess with me. I have one person telling me that the others are blaming my son, but no one is coming forward and telling me, to my face, that my son is the culprit. If they are good parents and, if they know my son and myself, then I would expect the common courtesy of them telling me of the trouble to my face and letting me deal with it on my own terms... unless it's all hear-say and no one has made a positive ID. Like I said, you can mess with me and I will fight my battles, but DO NOT mess with my mom or my child because then I will get upset...