Security was tight this morning around the CIA's suburban Washington headquarters as President Barack Obama joined agency leaders and personnel for a memorial service for the five CIA officers and two contractors who were killed by a suicide bomber in Khost, Afghanistan, on Dec. 30.

The bombing, which also killed a Jordanian intelligence officer, was the costliest attack against the agency since a 1983 strike on the U.S. Embassy in Beirut, Lebanon, which took the lives of eight CIA officers.

The bomber has been identified as Humam Khalil Abu-Mulal al-Balawi, a Jordanian extremist who the Jordanian intelligence service believed it had recruited as an agent to penetrate al Qaida.

Instead, al-Balawi offered his services to the terrorist network as a suicide bomber and reportedly gained access to the top-secret CIA base in Khost with a fake tipoff on the location inside Pakistan's nearby tribal area of al Qaida's No. 2 leader, Ayman Zawahri.