Plotters didn't know where mail bombs would go off

WASHINGTON - The plotters behind last week's unsuccessful mail bombings could not have known exactly where their Chicago-bound packages were when they were set to explode, even after a suspected test run, U.S. officials say.

The communication cards had been removed from the cell phones attached to the bombs, meaning the phones could not receive calls, officials said, making it likely the terrorists intended the alarm or timer functions to detonate the bombs.

"The cell phone probably would have been triggered by the alarm functions and it would have exploded midair," said a U.S. official briefed on the investigation of the bombs taken off cargo planes Friday in England and in the United Arab Emirates. This person, like other officials in this story, spoke on condition of anonymity to discuss the case.

The official also said Tuesday that each bomb was attached to a syringe containing lead azide, a chemical initiator that would have detonated PETN explosives packed into each computer printer toner cartridge. Both PETN and a syringe were used in the failed Christmas Day bombing of a Detroit-bound airliner linked to an al-Qaida branch in Yemen.

The Obama administration, which has been monitoring intelligence on possible mail plots since at least early September, was preparing new security rules for international cargo in response to the attempted attack.

Security officials are considering requiring that companies provide information about incoming cargo before planes take off, one U.S. official said. Currently, the United States doesn't get that information until four hours before a plane lands.

A second official said the United States will also expand its definition of high-risk cargo, meaning more cargo will be screened from countries known as hotbeds of terrorism.

President Barack Obama stressed the need for stronger security for air cargo in a telephone conversation Tuesday with Ali Abdullah Saleh, Yemen's president, the White House said.

Investigators believe al-Qaida mailed three innocent-looking packages from Yemen to Chicago in mid-September to watch the route they took.

One of those packages contained a copy of British author George Eliot's 1860 novel "The Mill on the Floss." Authorities were investigating whether it was a subtle calling card from Anwar al-Awlaki, the U.S.-born Yemeni cleric who has inspired a string of attempted attacks against the West.

The militant cleric is now a fugitive, targeted by a U.S. kill or capture list. Yemeni authorities put him on trial in absentia Tuesday, charging him as a new defendant in the October killing of a French security guard.

Al-Awlaki became well versed in English literature while in prison in Yemen from 2006 to 2007 and later posted online book reviews slamming Shakespeare and praising Charles Dickens.