When The Post last week broke news on a broad Justice Department investigation into a leak of national-security information regarding North Korea to Fox News reporter James Rosen, Fox News itself reacted as if the story was a bombshell.

Of course, it was: As The Post explained, the Justice Department had secured a search warrant to probe Rosen’s personal e-mail account in connection with the case. An affidavit described Rosen, who was pumping State Department security adviser Stephen Jin-Woo Kim for information on sensitive topics relating to U.S. foreign affairs, either an “aider, abettor and/or co-conspirator.”

Following the story’s revelations, Fox News’s airwaves filled up with discussion of the case. The network itself, too, issued a statement that indicated some level of surprise at the news:

We are outraged to learn today that James Rosen was named a criminal co-conspirator for simply doing his job as a reporter. In fact, it is downright chilling. We will unequivocally defend his right to operate as a member of what up until now has always been a free press.

The statement didn’t say that Fox News knew nothing of the matter. After all, the case involving Kim and Rosen has been public knowledge for at least three years. In June 2011, the New York Times wrote about it.

Yet Fox News somehow missed key developments. For example, the Justice Department seized various phone records pertaining to the case. That happened back in 2010, and according to a New York Times story, the Justice Department says it notified the company, but neither Fox News nor its parent company, News Corp., remembers having received anything on the matter. From the New York Times story:

A Fox News executive said the channel had never heard of the Justice Department investigation and had no knowledge of News Corporation ever being notified. A News Corporation spokesman said Sunday that the company was looking into the matter of notification. “While we don’t take issue with the D.O.J.’s account that they sent a notice to News Corp., we do not have a record of ever having received it,” Nathaniel Brown, the spokesman, said.

Astonishing. The legal world is downright freakish about the handling of documents — everything gets sent through various channels, sign-offs are required and so on. Indeed, the Times quotes a government official as saying that notification of the subpoenas in this case was made by “certified mail, facsimile and e-mail.” It being the 2010s, perhaps no one was standing by the fax machine.

Whatever the notification protocols, it’s not hard to believe that Fox News passed ignorant of the deep governmental snooping in the case. Had it known, after all, it could have gotten a jump start on all the story lines that it has been pushing since last week: That the Obama administration is overreaching, that it targeted Fox News and that Fox News does serious national-security reporting.