By Peter Finn and Greg Miller
Washington Post Staff Writers
Tuesday, November 2, 2010; 5:36 AM
The two package bombs discovered on cargo flights last week contained far more explosive material than the device that the alleged would-be underwear bomber planned to use last Christmas to down a Detroit-bound jetliner, according to German security officials.
The officials said the bombs were so expertly built that the wiring was difficult to detect even when seen in an X-ray image.
The German officials, who briefed reporters in Berlin, said the bomb found on a UPS plane in England, which also passed through the Cologne-Bonn airport, contained 15.11 ounces, or 400 grams, of the explosive PETN. The second device, found at a FedEx facility in Dubai, contained 10.58 ounces of the material, a powerful plastic explosive.
The PETN-based bomb found on Umar Farouk Abdulmutallab, the Nigerian accused of attempting to bring down a Northwest flight from Amsterdam to Detroit, weighed 2.82 ounces.
Meanwhile, U.S. officials disclosed Monday that authorities had tracked earlier suspicious packages from al-Qaeda's Yemen-based affiliate in September, attempts now seen as potential test runs for the foiled bombing attempt a month later.
A U.S. official said that three September shipments were also sent to an address or addresses in Chicago and contained books and religious literature, but no explosives. The official, who was not authorized to speak publicly on the subject, said that the packages were intercepted because of intelligence indicating that they had been sent by a person affiliated with AQAP.
One or more of the packages was allowed to continue to Chicago, but the U.S. official said that the concerns raised by that episode - first reported by ABC News - help to explain why the U.S. reaction was so swift to the Saudi intelligence tip last week.
The shipments of earlier packages might have enabled AQAP to monitor their delivery using tracking services commonly available on shippers' Web sites, information that might have been used in connections with timers or other devices to maximize the damage caused by bombs.
Both of the bombs discovered last week were encased in ink cartridges. One German official described the design as "highly professional," saying that some of the wires were so well disguised they they looked like cables for a printer. Other wires were so thin they couldn't be seen on an X-ray, the official said, echoing other analyses in recent days that the bombs could beat X-ray machines and bomb-sniffing dogs.
The bombs are believed to be the handiwork of Ibrahim Hassan al-Asiri, a Saudi national active in al-Qaeda in the Arabian Peninsula, the group behind the Christmas Day plot, among other conspiracies.
Explosive experts say that the amount of PETN in the ink cartridges could have brought the planes down.
Jimmie Oxley, co-director of the Center of Excellence for Explosives Detection, Mitigation and Response at the University of Rhode Island, said that if the packages ended up on a pallet surrounded by other cargo, the planes could have survived an explosion, but that if they had been placed near the skin of the planes, detonations could have destroyed the aircraft in mid-air.
"I've been involved in blowing up luggage, and placement determines everything," Oxley said.
Both packages were addressed to synagogues in Chicago, and Oxley said either could have killed someone if it had exploded while being opened.
On Tuesday, prosecutors in Yemen announced that they had charged Yemeni-American cleric Anwar al-Aulaqi with "promoting violence and the killing of foreigners," the Associated Press reported.
The whereabouts of Aulaqi, who U.S. intelligence officials believe was involved in the failed Christmas Day bombing attempt and has long promoted violence against the United States, are not known. Yemeni officials said he was being charged in absentia in the "Specialized Criminal Court" in Sanaa, the capital.
It is the first formal legal action Yemen has taken against Aulaqi, who was born in New Mexico.
On Monday, Germany said it would halt direct passenger flights between Germany and Yemen; Britain took a similar step in January after the failed Christmas Day bombing attempt. There are no direct flights between the United States and Yemen.
Britain said Monday that it would extend a ban on unaccompanied freight from Yemen to Somalia, citing links between terrorists in both countries.
Home Secretary Theresa May said Britain's security services had no information that other bombs have eluded detection.
"At this stage, we have no information to suggest that another attack of a similar nature by al-Qaeda in the Arabian Peninsula is imminent," May told parliament.
Meanwhile, investigators in the United Arab Emirates tried to head off speculation of a link between the package bombs and the crash of a UPS cargo plane in Dubai in September. There was no evidence that the plane was brought down by an explosion, UAE officials said this week.
The explosives in Dubai and England were intercepted after Saudi officials tipped off the United States and other countries that bombs were in transit and provided tracking numbers of the shipments to help intercept them.
Yemeni officials said Monday that the Saudis were told of the plot by Jabir al-Fayfi, a former Guantanamo Bay detainee, who fled the kingdom after his release in 2006.
But Gregory Johnsen, a doctoral candidate at Princeton University and an expert on Yemen, noted in his blog, Waq al-Waq, that al-Qaeda in the Arabian Peninsula announced Fayfi's arrest on Sept. 6, which seems too far removed from the latest plot to make him a credible informant. A U.S. official concurred.
Staff writer Karen DeYoung in Washington contributed to this report.