As a person who has been in a law enforcement career field for 22 years now, my immediate action would be to report the individuals to the local police department. The two individuals, if they are the guilty party, have committed either assault or aggravated assault which are felony crimes that shouldn’t go unpunished.
No, two wrongs don’t make a right and the process of vigilantism, while it may seemingly appear appropriate or necessary to some, isn’t the correct way to have the justice system work in the way it is currently intended to.
Just for the record, I think Pedophilia is a disgusting and abhorrent crime to the nth degree but I’m not comfortable and wouldn’t ever be comfortable taking the law into my own hands and engaging in behavior that would put me on the same level as criminals already out there. (i.e. – vigilantism)