Air travel security reviews under way after airliner attack

information as “sensitive.” He says Abdulmutallab checked into his flight with only a small carryon bag.

Abdulmutallab had been placed in a U.S. database of people suspected of terrorist ties in November, but there was not enough information about his activity that would place him on a watch list that could have kept him from flying. British officials, however, placed Abdulmutallab’s name on a U.K. watch list after he was refused a student visa in May.

Home Secretary Alan Johnson added that police and security services are looking at whether Abdulmutallab was radicalized in Britain.

Abdulmutallab received a degree in engineering and business finance from University College London last year and later applied to re-enter Britain to study at another institution. Johnson said Monday he was refused entry because officials suspected the school was not genuine and they then put his name on the list. Johnson says that people on the list can transit through the United Kingdom but cannot enter the country.

Officials said he came to the attention of U.S. intelligence last month when his father, Alhaji Umar Mutallab, a prominent Nigerian banker, reported to the American Embassy in Nigeria about his son’s increasingly extremist religious views. In a statement released Monday morning, Abdulmutallab’s family in Nigeria said that after his “disappearance and stoppage of communications while schooling abroad,” his father reached out to Nigerian security agencies two months ago. The statement says the father then approached foreign security agencies for “their assistance to find and return him home.” The family says: “It was while we were waiting for the outcome of their investigation that we arose to the shocking news of that day.” The statement did not offer any specifics on where Abdulmutallab had been.

Abdulmutallab’s success in smuggling and partially igniting the material on Friday’s flight prompted the Obama administration to promise a sweeping review of aviation security, even as DHS secretary defended the current system.

Gibbs, the White House spokesman, said the government will investigate its systems for placing suspicious travelers on watch lists and for detecting explosives before passengers board flights. Both lines of defense were breached in an improbable series of events Christmas Day that spanned three continents and culminated in a struggle and fire aboard a Northwest jet shortly before its safe landing in Detroit. Law enforcement officials believed the suspect tried to ignite a two-part concoction of the high explosive PETN and possibly a glycol-based liquid explosive, setting off popping, smoke and some fire but no deadly detonation.

An apparent malfunction in a device designed to detonate the PETN may have been all that saved the 278 passengers and the crew aboard Northwest Flight 253. No undercover air marshal was on board and passengers and crew subdued the suspect when he tried to set off the explosion. He succeeded only in starting a fire on himself.

Security experts said airport “puffer” machines that blow air on a passenger to collect and analyze residues would probably have detected the powder, as would bomb-sniffing dogs or a hands-on search using a swab. Most passengers in airports only go through magnetometers, which detect metal rather than explosives.

Abdulmutallab was treated for burns and was released Sunday to a prison fifty miles outside of Detroit.

Stiffer boarding measures have met passengers at gates since Friday and authorities warned travelers to expect extra delays returning home from holidays.

Forbes reports that adding to the airborne jitters, authorities detained a man, also from Nigeria, who locked himself in the bathroom on Sunday’s Northwest flight 253 from Amsterdam as it was about to land in Detroit. Investigators concluded he posed no threat. Despite the government’s decision after the attempted Friday attack to mobilize more air marshals, none was on the Sunday flight from Amsterdam, according to a government report obtained by the AP.