The suicide bomber who killed seven CIA agents in Afghanistan was a Jordanian informant, US media reports say.
He is said to have been a doctor recruited by Jordan’s intelligence service to infiltrate al-Qaeda.
He is believed to have been working undercover in eastern Afghanistan for weeks before detonating a bomb at Forward Operating Base Chapman.
The attack 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 have 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.
Jordanian intelligence believed they had brought him 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, who is a former CIA employee, said 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 told the Associated Press news agency.
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.