What did The State do with the Sanford emails between December and June?

Strictly as a question of journalism, I remain curious.

Editors at The South Carolina newspaper have explained that back in December they received, from an anonymous source, emails reportedly written by the governor and his girlfriend. But that editors could not authenticate them, and so they didn't run with any story, which is fine.

But what I've been wondering since is, exactly how hard did The State, which defended Sanford when he first went 'missing' last week, work to authenticate the emails?

Over the weekend, the paper reported:

A Dec. 30 e-mail planted the seeds of believability for a Tuesday-night phone caller who said Sanford had flown to Argentina.

Those anonymous tips led The State to have a reporter at the Atlanta airport to interview Sanford [last week]. Then, in rapid succession, the paper told Sanford's aides and a key ally, Davis, that it had e-mails describing an affair between Sanford and a woman in Argentina, and a free-lance journalist knocked on a door in Buenos Aires. A woman at that address initially answered to the name on the e-mails, Maria, then said Maria wasn't at home.

By my reading, that seems to indicate that The State, for the first time, notified Sanford and his key ally last week that the newspaper had the emails, which seems odd. Why didn't The State, as part of its authenticating process, do that in December, or January, or February?