The suicide bomber who killed seven CIA agents in Afghanistan was an al-Qaeda triple agent, US media reports say. He is said to have been a doctor from Jordan who was arrested by Jordanian intelligence a year ago. He was then reportedly recruited by the Jordanians and CIA - who thought they had successfully turned him - and given a mission to find al-Qaeda leaders. He is believed to have been working undercover in Afghanistan for weeks before detonating a bomb at a CIA base. The attack at Forward Operating Base Chapman was the worst against US intelligence officials since the US embassy in Beirut was bombed in 1983. The Washington Post quotes two former US government officials as saying that the alleged bomber lured the CIA officers into a meeting with a promise of new information on al-Qaeda's top leadership. The reports named him as Humam Khalil Abu-Mulal al-Balawi, a 36-year-old al-Qaeda sympathiser from Zarqa, Jordan, arrested by Jordanian intelligence over a year ago. The CIA has declined to comment on the reports. Changing sides Jordanian intelligence believed they had brought Humam al-Balawi over to their side and sent him to Afghanistan to infiltrate al-Qaeda, US network NBC says. His specific mission was thought to be tracking down al-Qaeda's number two, Ayman al-Zawahiri. According to Western intelligence officials quoted in the reports, Humam al-Balawi called his handlers last week to arrange a meeting at Forward Operating Base Chapman in Khost, where he said he would relay urgent information about Zawahiri. Once inside the base, the reports say, he blew himself up killing seven CIA employees and his handler, whom Jordanian media have named as Ali bin Zeid. Questions were raised after the bomb was detonated in the base's gym last week about how the attacker could have managed to pass through security. The Washington Post says he was picked up in a car outside the base and driven in without being thoroughly searched. A US official, also a former CIA employee, told the Associated Press news agency that such people were often not required to go through full security checks, in order to help gain their trust. "When you're trying to build a rapport and literally ask them to risk [their lives] for you, you've got a lot to do to build their trust," he said. Drone base A Taliban spokesman quoted on al-Jazeera's website said Humam al-Balawi was a double agent who had misled Jordanian and US intelligence services for a year. Forward Operating Base Chapman, a former Soviet military base, is used not only by the CIA but also by provincial reconstruction teams, which include both soldiers and civilians. The airfield is reportedly used for US drone attacks on suspected militants in neighbouring Pakistan. The CIA has not released the names of the officials killed nor details of their work because of the sensitivity of US operations. But the head of the base, reported to be a mother-of-three, was among those killed. The BBC's Mark Mardell in Washington says the CIA will be deeply embarrassed that the bomber was able to work so closely with the agency and with such high level officials. Source: BBC