"The tort of defamation refers to a false statement, either spoken ("slander") or written ("libel") that injures someone's reputation. However, some types of false statements are considered so damaging that they are deemed defamatory on their face ("defamation per se")."
Given the fact that William is the one who made the statements that made him seem like a child molester, he is the only one responsible for hurting his reputation.
His reputation was that he's a pedophile. He did that by posting what he posted. Also now that he's gone international in th newspaper, the entire world can make teir own conclusion of what they think about a man who repeatedly posted how he had actually taken indecent liberties with children.
There is nothing he or anyone can do about anybody calling him a child rapist because he himself said he had done so.
"Indications that a person was unchaste or engaged in sexual misconduct"
"Why are you saying he's a child molester?"
"Because he said several times that he had raped children and liked to touch children."
http://injury.findlaw.com/torts-and-personal-injuries/what-is-defamation-per-se-.html
Good luck with that defamation lawsuit!