The document, marked “secret” and still heavily redacted, makes a startling claim: The Pakistan government helped fund a suicide bombing in Afghanistan in 2009 that became the bloodiest attack on the CIA in a quarter-century.

“Foreign intelligence service and Haqqani network involvement in the 30 December 2009 suicide attack at [Camp] Chapman,” begins the subject line for the State Department cable, written in early 2010 by a U.S. official who was not named.

The memo, made public this week by a nonprofit group, proceeds to challenge the narrative of one of the worst days in the CIA’s history. It describes an elaborate plot in which Pakistan’s intelligence service allegedly put up $200,000 for the now-infamous bombing, which occurred when a presumed al-Qaeda informant was allowed into a secure U.S. base in Khost, Afghanistan, to meet with a team of American officers and handlers.

Once inside the base, the informant detonated his device, killing seven CIA officers and contractors as well as a Jordanian intelligence officer and an Afghan driver. It was the deadliest attack on CIA personnel since the U.S. embassy bombing in Beirut in 1983, and the document suggests that Pakistani government officials helped engineer it.

But is the claim credible? The new version of events has prominent skeptics, starting with the U.S. intelligence community, which was both targeted by the attack and also spent many months piecing together the evidence on how and why it happened.

That internal investigation concluded that the plot was cooked up by al-Qaeda and its allies in the Pakistani Taliban, and U.S. officials still maintain that no credible evidence exists of significant involvement by either the Pakistani government or the Haqqanis, a militant group that operates along the Afghan-Pakistani border and has sometimes allied with al-Qaeda in the past.

One U.S. intelligence official who studied the newly released document described its contents on Thursday as an “unverified and uncorroborated report”— essentially raw intelligence of the kind that routinely lands on the desk of U.S. analysts and diplomats in overseas posts. The redacted report says nothing about the source of the information, including whether the person was regarded as reliable or how the allegations were eventually assessed.

“The document clearly states that it contains unevaluated information,” said the official, who insisted on anonymity because much of the investigation into the bombing remains classified.

“The Haqqanis are brutal terrorists who continue to target innocent people, including Americans,” the official said. “Nonetheless, the general consensus is that the 30 December attack was primarily an al-Qaeda plot and did not involve the Haqqani network.”

The new document was obtained by the National Security Archives, a nonprofit organization based at George Washington University that routinely seeks the release of classified government documents through the federal Freedom of Information Act. It is part of a trove of formerly classified State Department cables pertaining to the Haqqanis, a clan that was officially declared a terrorist organization in 2012.

The memo, dated Feb. 6, 2010, is self-described as an “information report, not finally evaluated.” While almost entirely redacted, it contains a description of an alleged meeting between two Haqqani network members and unidentified representatives of Pakistan’s Inter-Services Intelligence division, commonly known as the ISI. The topic ostensibly was the funding of a suicide mission by Humam al-Balawi, a Jordanian physician who was tapped by the CIA to spy on the Taliban and al-Qaeda officials in 2009. By late 2009, Balawi had been operating in Pakistani’s northwestern tribal region for several months, passing to the Americans detailed information about the jihadists’ leadership. In reality, Balawi was an al-Qaeda sympathizer who agreed to work with the terrorists in luring the Americans into a deadly trap.

According to the memo, the Pakistani officials provided the Haqqanis with $200,000 at the meeting “to enable the attack on Chapman,” the U.S. base at Khost that served as a listening station for intelligence operatives. Half the money was promised to an Afghan border guard commander named Arghawan, who was to help Balawi gain access to the U.S. base so he could carry out the bombing, the memo asserts.

Arghawan was in fact the man assigned by the CIA to pick up Balawi at the Pakistan border and drive him to Khost for the meeting. But his involvement in any plot would appear doubtful, as he was killed along with seven Americans when Balawi detonated his bomb.

The memo alleges that the Haqqanis pocketed Arghawan’s presumed share of the money “because Arghawan died during the suicide attack.”

Countering the memo's claims somewhat are video recordings made by Balawi and Taliban leaders prior to the suicide bombing, as well as statements and essays by al-Qaeda officials describing plans for the attack. The videos — essentially an advance claim of responsibility — insist the bombing was intended to exact revenge for earlier CIA drone strikes that killed Taliban and al-Qaeda leaders in the region.

“Death will come to you [in] unexpected ways,” Balawi warns the CIA in one video recorded a few days before his suicide bombing.

The recording makes no mention of sponsorship by the Pakistani government or the Haqqanis. At  time of the attack, Pakistan was engaged in bitter fighting with the Taliban and had killed hundreds of the group's fighters that year in a ground offensive, making it unlikely that its government would willingly turn over money to assist what was essentially a Taliban operation.

Pakistan on Friday dismissed as “preposterous” the claim of government sponsorship of the attack.

“In fact, we were shocked and deeply saddened when precious American lives were lost at the Chapman facility in 2009 in an unfortunate attack that was later claimed by TTP [Pakistani Taliban] in a publicly available video, featuring the suicide bomber with the leader of the TTP,” said a statement issued by a government spokesman in Islamabad.

“We wish to remind that Pakistan is among the biggest victims of terrorism, having lost tens of thousands of innocent lives, including over five thousand valiant personnel of law enforcement agencies, and economic losses to the tune of a hundred billion dollars,” the statement said.

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