If the article on the "local news site" was false, or cannot be proved true and if it harmed, or was likely to harm, the reputation of the alleged scammer, it was probably defamatory. Repeating a defamatory statement can itself be defamation. Whether it is in fact defamation depends on whether the repetition was done in a way likely to be seen as endorsing the original story, or in a way that contests it, or in a way that neutrally analyzes it without either endorsing or contesting the original story.
Posting a link to a news story is less likely to be held to be defamation than would repeating the whole story, or its defamatory statements. However, if the link was so distributed that it significantly spread defamatory statements, it might itself constitute defamation.
In any case, even if the statements can be proved true, or the poster has another clear defense to an accusation of defamation, defending a suit can be costly and troublesome.
In some jurisdictions there are so-called "anti-SLAPP" laws. These can be invoked when a defamation suit is used to unduly burden speech that is of public value, sch a news reporting or comments on current public issues. (SLAPP stands for "strategic lawsuit against public participation".) Such laws can be used to have an improper suit dismissed at an early stage, before undue burdens are imposed. Exactly how and when such laws may be invoked varies depending on the jurisdiction, and they do not exist at all in some jurisdictions. One would be wise to consult a lawyer knowledgeable in defamation law to see if a anti-SLAPP law, or some other tactic, could avoid a burdensome suit.
A threat to sue from a person noted from having sued others with some frequency would usually be grounds for concern.
