Would you intervene in a possible child kidnapping?

What if you were walking down the street, and you saw a man that just grabs a child (9–12 years old) and the man is screaming
to the child “There you are do you know how long I have been looking for you?” ” Come with me now, your mother is worried sick! ” The child is screaming ” No, let me go! I do not know you, you are not my Dad!” Would you really get involved in something like that? If you would, how would you get involved?