Blogs and Lashon Ha-Ra III

In my previous post, I wrote: "One may discuss negative stories about general public leaders provided that one is certain that the stories are true (or adds appropriately worded caveats)"

A commenter asked where permission is mentioned to relay stories about which one is not entirely certain, as implied by the parenthetic remark above. See Hafetz Hayim, Hilkhos Rekhilus, chapter 9 note 9 and note the important details and caveats.