Both the Obama administration and news network CNN knew that the Septemeber 11, 2012 attack in Benghazi, which killed four Americans, was carried out by the Islamist militant group Ansar al-Sharia but hid that information from the American people until after the 2012 presidential election.

Obama administration officials knew Ansar al-Sharia had claimed responsibility for the the attack. It’s in the emails that were leaked in October 2012. The email was sent from a redacted email address at Hillary Clinton’s State Department.

As Reuters reportedon October 23, 2012:

Officials at the White House and State Department were advised two hours after attackers assaulted the U.S. diplomatic mission in Benghazi, Libya, on September 11 that an Islamic militant group had claimed credit for the attack, official emails show.

The emails, obtained by Reuters from government sources not connected with U.S. spy agencies or the State Department and who requested anonymity, specifically mention that the Libyan group called Ansar al-Sharia had asserted responsibility for the attacks.

Not only did they the U.S. government know that the attack was carried out by Ansar al-Sharia, but anyone watching CNN’s show Anderson Cooper 360°, featuring Anderson Cooper, on the night of the attack knew it too.

AC360 reporter Jomana Karadsheh named Ansar al-Sharia as the attackers live on the air, in a report that happened in the middle of the attack.

Here’s what Karadsheh told Cooper:

Well Anderson, according to the eyewitness up to about an hour ago he describes the situation there as a frontline. Libyan security forces were engaged in heavy clashes with members of an armed group; that is Ansar Al Sharia, that is a radical militant group that is based in eastern Libya. He also reported rocket propelled grenades hitting the consulate building. Libyan army troops were deployed. Roads were blocked off by military vehicles.

Here is the full segment as it aired live that night:

When Anderson Copper’s CNN show AC360 ended on the night of September 11th, 2012, it was 9:00 PM in Washington, D.C. and 3:00 AM in Benghazi. Ambassador Chris Stevens and Sean Smith were dead. There was a firefight going on outside the CIA annex. Glenn Doherty and Ty Woods were still alive. CNN had just reported on live TV that Ansar al-Sharia had launched the attack on the mission in Benghazi using RPGs and that they’d blocked off the roads. Three hours earlier, the email had been sent to the White House, CIA, State Department officials, and others, stating that the attack on Benghazi was carried out by Ansar al-Sharia.

After Anderson Cooper and CNN producer Jomana Karadsheh reported the truth about Benghazi on the night of September 11th, what was their follow up on September 12th? To attack Mitt Romney.

Cooper did a “Keeping Them Honest” segment on September 12th titled, “Libya attack now campaign controversy.” The description on the AC360 website reads:

Mitt Romney is accusing the White House of apologizing to the mob that attacked the U.S. consulate in Benghazi, Libya. Anderson Cooper is Keeping Them Honest.

Another segment on the September 12th show was called, “The timing of Romney’s Libya criticism.” It focused on nitpicking Mitt Romney’s reaction to the terror attack. Cooper’s guest Cornell Belcher called Romney “craven” and said Romney should be disqualified from being elected president based on his criticism.

Cooper—who had reported 24 hours before that the attack was by Ansar al-Sharia—asked guest Ari Fleischer if Mitt Romney’s statement should have waited “since full details weren’t known.” Cooper makes no mention at all of the significant detail that his own show reported. Romney’s statement came after Cooper’s show has aired.

For some reason, Cooper chose not to focus on the attack that killed four Americans and the al-Qaeda-affiliated group behind it—information Cooper had reported just the night before.

On September 19th, Cooper once again reported on Benghazi, reporting what National Counterterrorism Center Director Matthew Olsen had testified earlier that day. Cooper mentioned that officials were looking for a connection for al-Qaeda affiliates but once again made no reference whatsoever to what his own show had reported live on the air eight days earlier.

The first official acknowledgment that Benghazi was a planned attack by Ansar al-Sharia came from Former CIA Director David Petraeus on November 12, 2012—six days after the re-election of President Obama.

Once again, AC360 covered the story, and Anderson Cooper acted surprised to hear that Ansar al-Sharia was behind the attack in Benghazi. After being told CIA Director Petraeus would be telling Congress that he knew “immediately” that the attack on Benghazi was carried out by Ansar al-Sharia, Cooper said to Pentagon reporter Barbara Starr:

This is really interesting to me. Just to be clear, your source is saying General Petraeus knew almost immediately or that he felt that it was terrorist attack, knew the group involved…

Cooper makes no mention that his own show also knew the group involved, immediately.

CNN reported that night, “Ex-CIA chief Petraeus testifies Benghazi attack was al-Qaeda-linked terrorism,” information that was held from Congress until after the election.

The hearing was closed but New York Congressman Pete King spoke to reporters afterwards and said this conflicted with previous accounts.

King said Petraeus’ testimony differed from an earlier assessment the former CIA director gave lawmakers just days after the September 11 attack, which left four Americans dead, including U.S. Ambassador Chris Stevens.

“He (Petraeus)… stated that he thought all along he made it clear that there was significant terrorist involvement, and that is not my recollection of what he told us on September 14,” King said.

“The clear impression we were given (in September) was that the overwhelming amount of evidence was that it arose out of a spontaneous demonstration, and was not a terrorist attack,” he said.

Rep. King’s belief that the information supplied by the Obama administration had changed was correct.

Follow Breitbart News investigative reporter and Citizen Journalism School founder Lee Stranahan on Twitter at @Stranahan.