The Right Thing

So I have this friend w/ two sons.  The younger of the 2 lives w/ his father but the 8yr old lives w/ his mom and soon to be step father.  Today I found out that something happened that caused the step father to have to alledgely restrained said child.  What actually went down is still unclear. At first I was told that Ethan threw a pinecone @ Chris and he grabbed him by the arms and threw him to the ground.  Later on, the story became that Ethan was being violent and needed to be restrained.  But what could an 8yr old have possibly done that would cause a 30yr old man to do something that would have him checking for bruises later on?  Something about that story doesn't sit right w/ him.  I spoke w/ the boys gramma who was understandably upset and it was after that, that the story suddenly changed.  So what do you think?  Did I do the right thing by telling somebody what I had heard?