As most people know, these two peers aren't exactly BFF with suchmoon. Claiming you got your information from an anonymous source is no defense for libel. My red tag will remain in place until I'm convinced this allegation is more likely than not to be true. So far, it isn't.
In order for something to be libel, it needs to be proven false, and cause damages, often via harm to their reputation, but can also be to decreased business income and similar.
The fact a statement can not be proven to be true is not libel, the statement must be proven to be false. Suchmoon admits above she cannot prove the OP to be false:
I could ask admin to access my PMs but that would prove nothing (I could have deleted the alleged messages).
I am also not aware of any business that suchmoon conducts around here on any regular basis, so I cannot say she would win damages, even if she proved the OP to be false.
The statement doesn't need to be "proven" false, it needs to be proven true. The truth is an affirmative defense against defamation. And one only needs to show that the statement is more likely than not. You should know that logically, its much harder to prove something is false. The only way is to prove something is false is to show that the assumption that it is false leads to a contradiction. Also, in most jurisdictions in the US, accusing someone of a crime that turns out to be untrue is "defamatory per se" and doesn't require someone to prove the have had real monetary damages.