(CNN) -- The suicide bomber who killed seven CIA officials and a Jordanian military officer last week in Afghanistan was a Jordanian double-agent, a former U.S. intelligence official told CNN Monday.
The bomber was a source who came to the base camp in Khost near the Pakistan border for a meeting on December 30, a senior U.S. official also confirmed.
The man had been used by both countries' intelligence services in the past, and had provided information about high-value targets, the senior U.S. official said.
"Yes, it was a joint U.S.-Jordanian source who had provided over the period of his cooperation a lot of very detailed good information that was of high interest at the most senior levels of the U.S government," the former U.S. intelligence official said.
The security breach occurred because the bomber was met off-base by U.S. intelligence officials who failed to search him before they put him in a car and drove him onto Forward Operating Base Chapman, the former intelligence official said.
Both the Jordanian and U.S. intelligence services believed the man was loyal, according to the former intelligence official.
"Clearly there is a lot of soul searching" at CIA headquarters in Virginia, according to the former intelligence official.
The bomber was identified as Human Khalil Abu-Mulal al Balawi, from the Jordanian town of Zarqa, also home to the late Abu Musab al Zarqawi, the one-time leader of Al Qaeda in Iraq, the former intelligence official said.
Both the Jordanian and U.S. intelligence agencies apparently believed al Balawi had been rehabilitated from extremist views and were using him to hunt Ayman al Zawahiri, the second-ranking al Qaeda official to Osama bin Laden, the former intelligence official said.
Jordanian intelligence services have long covertly cooperated with the United States, specifically in the hunt for al Zawahiri and bin Laden, because of the ability of Jordanian agents to blend into the al Qaeda organization, noted the former intelligence official.
Also killed in last week's attack in Afghanistan was Jordanian Army Captain Sharif Ali bin Zeid, a cousin of King Abdullah of Jordan. The Jordanian government has not publicly commented on the specific circumstances of bin Zeid's death, but U.S. sources confirmed bin Zeid was present and was the Jordanian operative working closely with al Balawi.
The CIA refused to comment Monday, saying the matter was under investigation. The bodies of the seven CIA employees were flown to Dover Air Force Base in Delaware to a private ceremony attended by CIA Director Leon Panetta, other agency and national security officials, and friends and family.
A Jordanian official who did not want to be identified said bin Zeid "was killed on Wednesday in the line of duty as he was taking part in a humanitarian mission carried out by the Jordan Armed Forces inAfghanistan."
The Jordanian official added: "Jordan's position in the war on terror is clear; we are fully committed to fighting al Qaeda, which is a threat to Jordan as it is a threat to the United States. We are also committed to continuing our cooperation with the United States and the international community in the fight against terror and in defeating al Qaeda."
In a posting on its Web site last week, the Taliban in Afghanistan claimed the bomber was an Afghan National Army soldier.
On Sunday, however, Pakistani Taliban chief Hakimullah Mehsud said in an e-mail that "we claim the responsibility for the attack on the CIA in Afghanistan."
"The suicide bomber was a Jordanian national. This will be admitted by the CIA and the Jordanian government" the message said.
The attack occurred at a forward operating base, which a U.S. intelligence official acknowledged was a crucial CIA post and a "hub of activity." The main purpose of CIA forward operating bases in Afghanistan, officials have noted, is to recruit informants and to plan and coordinate covert operations, including drone surveillance and targeting.
The attack was "a huge blow, symbolically and tactically," because it eliminated such a large number of CIA officers, who can require years to become ingrained in the region, said Reva Bhalla, director of analysis for STRATFOR -- an international intelligence company. In addition, the attack showed the ability of the Taliban to penetrate perhaps the most difficult of targets -- a CIA base, she said.
Former CIA official Robert Richer called it "the greatest loss of life for the Central Intelligence Agency since the Beirut Embassy bombing" in 1983, which killed eight agents.
An American intelligence official vowed last week that the United States would avenge the attack. Two of those killed were contractors with private security firm Xe, formerly known as Blackwater, a former intelligence official told CNN. The CIA considers contractors to be officers.
On Sunday, a local administration official and an intelligence official told CNN that two guided missiles struck a compound in the Pakistani village of Musaki in North Waziristan suspected of being a gathering place for local and foreign militants.
The attack killed Sadiq Noor, a teacher; his 9-year-old son; and three people from outside the country, according to the sources, who said the missiles were believed to have been fired by an unmanned drone. There was no immediate U.S. confirmation of the missile attack.