Aug. 9, 2013 -- President Obama surprised aides when he revealed today the existence of a sealed indictment in the Benghazi, Libya, attack, leaving some wondering if he crossed a legal line.

At a press conference at the White House, President Obama was asked whether justice would come to those responsible for the terrorist attack nearly a year ago in Benghazi, Libya, that killed four Americans, including the U.S. ambassador.

"[W]e have informed, I think, the public that there's a sealed indictment," the president responded. "It's sealed for a reason. But we are intent on capturing those who carried out this attack, and we're going to stay on it until we get them."

That marked the only official confirmation so far of a sealed indictment in the Benghazi case. For days, officials across the law enforcement and intelligence communities have refused to publicly confirm reports of a sealed indictment.

After all, according to federal law, "no person may disclose [a sealed] indictment's existence," and a "knowing violation … may be punished as a contempt of court." Contempt of court carries a maximum sentence of six months in jail.

A U.S. official, speaking on the condition of anonymity, called the president's disclosure "crazy."

"Doesn't the law apply to the president too?" the official asked, and then jokingly added, "I guess he could pardon himself."

In fact, though, the president is effectively immune from breaking the law when it comes to a sealed indictment, according to a former prosecutor in the Justice Department's Public Integrity Section

"The [president], by virtue of his position, can't violate any non-disclosure/confidentiality rule," said Peter Zeidenberg, now in private practice in Washington. "One of the perks of being the head of the executive branch: Nothing he says is technically a leak. If he does it, it is authorized."

However, Zeidenberg acknowledged "an argument could be made that a sealed matter can only be unsealed by a court."

Zeidenberg helped lead the investigation into who leaked the secret identity of CIA agent Valerie Plame in 2003 and the subsequent prosecution of vice presidential aide "Scooter" Libby for lying to federal officials about his role in all of it.

After the president's remarks, a spokesman for the U.S. Attorney's Office in Washington, where the sealed indictment is believed to have been filed, still declined to comment about reports of a sealed indictment in the Benghazi probe. An email asking specifically about the president's remarks was not immediately returned.

Despite the president's chosen words, a White House official insisted he "was simply referencing widely reported information and was not asked about, nor did he comment on any specific indictment."

A Justice Department spokesman declined to comment,

ABC News' Mary Bruce contributed to this report