Okay, I'm the first person to advocate reverse abortion/euthanisia/Star Chamber but did anyone wonder whether it was possible that the accusation was not true?

The information in the article is limited but I would not want to go off and beat, much less kill, someone on the mere statement from my wife that the neighbor molested my child. I'm not saying that I wouldn't feel the rage to kill the guy but one should better be damned sure that the guy did it before going medevial or otherwise, on him. If it turned out that the guy wasn't guilty, then any chance of a sympathetic jury walking you would be nil.
So assuming the guy did as he was accused of, I would want to kill him too but as a couple of others have stated, the cost of it is far too great and creates the additional victimization of my own family having to go through the crap that would follow, including but not limited to my lengthy incarceration. It would be an unfair trade: the life of a child molester for the life of a caring father. Yes, the legal system can be slow and frustrating but it is the best way. Once in prison, we could hope for a "Dahmer".