It doesn't seem to me that someone disgruntled would post an update apologising for the use of incorrect information about her in such an apologetic manner.
"Update January 4: The original version of this story said that Carolyn Doran's hit and run DUI resulted in a fatality. This was based on two separate sets of computer records - one with the Loudoun County, Virginia Circuit Court and another on the web site of the Virginia Judicial System. But these records are incorrect. Apologies to Carolyn Doran and her family."
Claiming someone killed somebody when they didn't and then not retracting the statement once you find out would be a very serious issue. The initial publication isn't libel, since they genuinely believed it at the time of publication and they did make an effort to verify it, but not retracting it might make it libel - I would have to look that up.