terror couples Arrested Yemeni Woman Believed to Be Half of a Terrorist Couple 
 
 The twentysomething Yemeni woman arrested yesterday in connection with Friday's foiled plot to send bombs to Chicago is reportedly a medical student whose role in the plan was mailing the explosive packages. A source said she's the spouse or girlfriend of an Al Qaeda operative, also believed to be part of Friday's terror scare, who's being searched for now. [NYDN] ||||| Yemen on Sunday released its only suspect in the failed plot to send two explosive-laden packages from Yemen to the U.S., as it emerged that the devices could have gone off aboard passenger planes—underlining the difficulties in finding the plotters and in plugging gaps in air security. 
 
 The surprise release came after at least one senior Yemeni official had questioned the arrest and amid accusations, which Yemen denied, that the young female suspect had been tortured. 
 
 The discovery in England and Dubai of the two explosive-laden packages, sent by air from Yemen, set off a global terror scare on Friday, and American and British investigators were on their way to San'a late Sunday to help investigate the failed plot. Officials in the U.S. and the United Arab Emirates have said the devices bore the hallmarks of al Qaeda, raising fresh worry about the growing sophistication and ambition of al Qaeda in the Arabian Peninsula, or AQAP, the Yemeni affiliate of the global terror outfit. 
 
 Five hundred students have been protesting on Sunday in Sanaa against the arrest of their colleague Hanan al-Samawi, arrested on Saturday by the Yemeni police on suspicion of having mailed bombs found on cargo planes. Video courtesy of AFP. 
 
 Over the weekend, details of the journey of the two packages emerged, underscoring lingering vulnerabilities in civilian air travel and transport almost a decade after the Sept. 11, 2001, attacks. 
 
 Qatar Airways said one of the packages traveled without detection on two separate passenger jets, from San'a to Doha and then to Dubai. German authorities attempted to stop the trans-shipment of a second suspected bomb late Thursday or early Friday, but discovered the material already had been forwarded from Cologne Airport to East Midlands Airport in the U.K., a spokesman for the German interior ministry said. 
 
 Amid concerns that more such packages may be en route, the U.S. Postal Service and the European Union said they have temporarily suspended acceptance of inbound international mail from Yemen. Yemeni officials said Sunday they are considering screening all parcels leaving Yemeni territory. 
 
 President Barack Obama's top counterterrorism adviser, John Brennan, told CNN on Sunday that the packages were "destined for a particular location in the United States and Chicago, but it appears as though they had the capability to be detonated on board that aircraft," and could have brought the planes down. 
 
 In a separate interview, Mr. Brennan said it appeared as though the packages were designed to be detonated in flight. 
 
 Enlarge Image Close Reuters Veil-clad women Sunday in San'a, the Yemeni capital, next to a car with a sticker showing President Ali Abdullah Saleh, right, and his eldest son. 
 
 U.K. Prime Minister David Cameron also said the device was designed to go off on an aircraft, and U.K. Home Secretary Theresa May described it as a "viable" explosive devise powerful enough to bring down a plane. 
 
 A person familiar with the probe said investigators are tracing parts and serial numbers of components of the devices found in England and Dubai, and are sharing that information to help identify the bomb maker. 
 
 In the Dubai device, the bomb maker modified a standard Hewlett-Packard printer, hiding an improvised explosive device in the toner cartridge. The device appeared to be wired with the motherboard of a cellphone. But the phone components didn't include a SIM card, suggesting it might have been built to be triggered by the phone's timer and not by an outside phone signal, according to the person familiar with the probe. 
 
 Another person familiar with the investigation said the device found in England also had used parts of a cellphone. 
 
 View Graphics See the locations where the packages originated and were found, and where other planes were investigated. More photos and interactive graphics 
 
 According to officials, the two packages contained a powerful and hard-to-detect type of explosive known as PETN, the same substance used by AQAP in a failed plot to blow up a U.S.-bound passenger plane last Christmas Day. Officials said the two packages appeared to contain as much as four to six times the amount of PETN as AQAP used in the Christmas Day plot. 
 
 Authorities familiar with the devices say the sophisticated wiring and the explosives used suggested they may have been the work of Ibrahim Hassan al-Asiri, the chief bomb maker for al Qaeda in Yemen. 
 
 "He is being looked at closely given his experience with explosives," a U.S. official said. 
 
 After the Christmas Day incident, the U.S. stepped up a secret military campaign to kill AQAP leaders, including American-born radical cleric Anwar al Awlaki. Known for his fiery sermons on the Internet, Mr. Awlaki encourages followers to take opportunities where they can and not wait to develop elaborate plots. 
 
 Though AQAP hasn't claimed responsibility for the Yemen packages, and no clear link to Mr. Awlaki has been established, officials in the U.S. believe it spearheaded the attempts. 
 
 On Saturday, U.S. officials said they believed both packages were shipped by individuals with possible links to two schools, the Yemen American Institute for Languages-Computer-Management, known as YAI, and the American Center for Training and Development, or ACT. 
 
 Officials offered few details about the institutions. The names of the school aren't well-known in San'a, which has an abundance of language and technical-training institutes using "American" in their titles. 
 
 Yemeni President Ali Abdullah Saleh said Saturday that Washington passed on a telephone number that led security forces to an engineering student, whom Yemeni security forces arrested Saturday. According to a person familiar with the probe, Yemeni authorities traced one of the parcels to the student because the package's paperwork contained her phone number and address. 
 
 Yemeni officials took her and her mother into custody Saturday evening. 
 
 "They claim that they found her phone number [from] the package, but that is not concrete evidence," said Abdul Raman Barman, the woman's lawyer, in an interview. "Anyone could have written her number [on] the package." 
 
 A human-rights group with which the attorney is affiliated said the woman had been subjected to beatings and cruel treatment. 
 
 A Yemeni official said those accusations were baseless and politically motivated. The official said the suspect was released on bail late Sunday, but isn't allowed to travel outside the country. The official said the shipping agent who took delivery of the package with the suspect's details was called in and asked to identify her, and said she wasn't the person who signed the manifest. Yemeni authorities concluded someone had stolen the young woman's identity, this official said. On Sunday, Qatar Airways confirmed that the Dubai package was transported aboard one of its jets from San'a to Doha, then to Dubai, where it was discovered. That raised an alarm that a passenger plane, not just a cargo plane, had transported the explosives. 
 
 Authorities in Dubai confiscated one explosive-laden parcel at a FedEx Corp. packaging center overnight Thursday that had originated in Yemen. A similar package was confiscated in a cargo-distribution center at East Midlands Airport in England. That shipment had been aboard a United Parcel Service Inc. plane and also had been sent from Yemen. 
 
 The airline said it carried out all required security procedures, and that the explosive device was of such a sophisticated nature that it wouldn't have been detected by X-ray machines or sniffer dogs. 
 
 The German police investigative agency, meanwhile, forwarded the identification information of the second package to their British counterparts after being alerted to it and realizing it had already left Cologne, bound for England. After alerting British officials, authorities there located the explosive. 
 
 The German agency acted on a tip from Saudi authorities, a person familiar with the investigation said. The spokesman for the interior ministry said the tip came from a partner service. 
 
 German Interior Minister Thomas de Maizière postponed a planned trip to Israel to oversee an investigation into why the shipment wasn't halted prior to shipment to Britain. Germany has temporarily halted air-freight shipments from Yemen, the interior ministry spokesman said. 
 
 U.S. officials have also said that Saudi Arabian intelligence tipped off Washington over the packages. A person familiar with the probe said there had been an infiltration of a militant circle in Yemen that led to the tip-off, but the person didn't provide details. 
 
 —Hakim Almasmari, Margaret Coker, Stephen Fidler, Alistair MacDonald and David Crawford contributed to this article. 
 
 Write to Chip Cummins at chip.cummins@wsj.com
– Yemeni officials yesterday detained two people thought to be connected to the recent bomb plot, but the sole suspect has reportedly been released. Hanan Al-Samawi, an engineering student, was detained along with her mother, who was not considered a suspect. Paperwork found on one of the manipulated packages contained Al-Samawi’s address. Her family and acquaintances have defended her, and her lawyer was quick to blame “identity fraud,” the Wall Street Journal reports. Now, the woman’s father says she has been released. (Earlier reports suggested she may be the wife or girlfriend of an al-Qaeda operative.)