Reporting from Washington — The two bombs concealed in U.S.-bound packages found on cargo planes in Britain and the United Arab Emirates were wired to explode, at least one via a cellphone detonator, and were powerful enough to bring down an aircraft, U.S. and British officials said Saturday.
A Yemeni official in Washington said a woman was arrested in Yemen in connection with sending the packages and that a relative, whom the official identified as either her mother or sister, was being interrogated.
"The woman was arrested based on a tip from foreign intelligence," said the official, who asked not to be identified. "Her name and phone number were provided."
Yemeni President Ali Abdullah Saleh said in a short news conference Saturday that Yemeni forces acted on a tip from U.S. officials, who had passed along a telephone trace.
The two bomb packages, addressed to Jewish organizations in Chicago, were intercepted Friday in airports in Dubai, United Arab Emirates, and East Midlands, England, after a detailed tip from Saudi intelligence that included package tracking numbers, U.S. officials say. The Dubai package was sent via FedEx, and the package to England went via UPS. Initial reports had said that both were UPS parcels and that both had been found late Thursday.
A search of 15 other suspicious packages from Yemen turned up no bombs, a U.S. law enforcement source said.
U.S. officials are still trying to piece together the intent of the plot, which they suspect was carried out by Al Qaeda in the Arabian Peninsula, the terrorist network's affiliate in Yemen.
It's unclear how the Saudis were clued in, but this month a leader of the Al Qaeda branch in Yemen, Jabir Jubran Fayfi, turned himself in to the Saudi government. Picked up by U.S. forces in Afghanistan in 2001, he had been held at the U.S. prison at Guantanamo Bay, Cuba, before being turned over to Saudi Arabia. He went through a rehabilitation program for militants and was released, only to rejoin Al Qaeda in 2006.
But Fayfi contacted Saudi authorities from Yemen to express his regret and readiness to surrender, the Saudi Interior Ministry said in a statement Oct 15.
On Saturday, authorities were investigating whether the plot sought to blow up the cargo planes in midair or upon landing — or whether the bombs were intended for the Chicago addresses on the packages.
British Home Secretary Theresa May said Saturday in London that the target of the bomb found in her country may have been an aircraft, though "we do not believe that the perpetrators of the attack would have known the location of the device when it was planned to explode."
As President Obama campaigned this weekend, he kept tabs on the investigation. He discussed the plot in phone calls Saturday with British Prime Minister David Cameron and Saudi King Abdullah.
Rep. Jane Harman (D-Venice), after briefings from Transportation Security Administration chief John Pistole and Homeland Security Secretary Janet Napolitano, said in an interview that the bombs were fashioned out of the chemical explosive PETN, the substance used in the attempt to bring down a Detroit-bound U.S. airliner on Christmas Day.
"But this was 10 times bigger," said a federal law enforcement official, who said the packages contained "about a pound each" of PETN.
"The fact that PETN was used in this plot is worrisome," said a U.S. intelligence official not authorized to speak for attribution. "PETN is hard to detect and lends itself to being concealed. It is not hard to make, but it takes some sophistication to conceal the explosives in the right way. It packs a punch. You don't need that much of it to blow a hole in an aircraft."
U.S. officials have said that the Christmas Day bomb was built by Ibrahim Hassan Asiri, who also reportedly built a PETN device in an unsuccessful attempt to kill the top Saudi counter-terrorism official last year.
One of the bombs found Friday was wired for remote detonation via cellphone, Harman said, and the other was linked to a timer but lacked a triggering device. The remote detonation setup "leads me to speculate that … people had [detonators] on the ground somewhere in Chicago," she said.
At least one of the addresses in Chicago was for a church that had been used at one time by a Jewish congregation, but not for seven years. The bomb discovered in Dubai was wired to a SIM card, a portable memory chip typically used in mobile phones, said Rep. Michael McCaul, a Texas Republican who serves on the intelligence and homeland security committees.
"The bombs were made to look like ink cartridges — like for a big Xerox machine," he said.