Al Qaeda Linked To Attempted Bombings

(CNN) -- Al Qaeda bomb maker Ibrahim Hassan al-Asiri, who is thought to be in Yemen, is linked to two explosive packages found on airplanes Friday, a federal official told CNN Sunday.

Separately, an engineering student has been arrested there as authorities investigate an apparent plot to bomb airplanes with devices hidden inside computer printers, a human rights lawyer in the poor Arab country told CNN Sunday.

The student, Hanan Al-Samawi, is a fifth-year student at Sanaa University, in the capital, said the lawyer, who said he has been asked to represent her.

Her mother, Amatulillah Mohammed, has also been arrested, Abdul-Rahman Barman told CNN, calling the arrest of the mother illegal.

The lawyer and human rights activist does not know where they are, he said, saying that holding them in an unknown location "is a criminal act."

The student's father, Mohammed Al-Samawi, said she is innocent, according to Barman.

The two devices found Friday on planes heading for the United States look like they were put together by the same bomber who designed last year's failed Christmas Day underwear bomb, a U.S. government official told CNN.

"The thinking is it's the same person or group of people that built the underwear bomb, because of the way it's put together," said the official, who had been briefed by multiple U.S. authorities and law enforcement sources. "But this one is about four times as powerful."

American authorities are now endorsing British Prime Minister David Cameron's position that the explosives were designed to take down an airplane, the official said.

One package was found in Dubai in the United Arab Emirates. The other was discovered at an airport in England. They were addressed to synagogues in Chicago, Illinois.

The device found in England was viable and could have taken down the plane, British Home Secretary Theresa May said Sunday in an interview on the BBC.

American and British authorities think al Qaeda's branch in Yemen is linked to the plot.

A key figure in the group is the American-born Yemeni militant cleric Anwar al-Awlaki, whom U.S. authorities have linked to Fort Hood shooting suspect Maj. Nidal Hasan and the man accused in the Christmas Day bomb attempt.

President Barack Obama's top counterterror aide, John Brennan, Friday declined to name al-Awlaki specifically as a suspect.

"Anybody who's associated with al Qaeda in the Arabian Peninsula is a subject of concern," he said.

Yemen is investigating the shipping agency that sent the packages, its President Ali Abdullah Saleh said Saturday, based on information provided by the United States and United Kingdom, who in turn are getting tips from Saudi Arabia.

The United Kingdom is sending a security team to help with Yemen's investigation, Saleh said.

A specific explosive was found in both Friday's devices and in the foiled underwear bomb attempt in 2009, a source close to the investigation said.

It's a highly explosive organic compound called PETN, which belongs to the same chemical family as nitroglycerin, the source said. Six grams of PETN are enough to blow a hole in the fuselage of an aircraft.

PETN was allegedly one of the components of the bomb concealed by Umar Farouk AbdulMutallab, the Nigerian man accused of trying to set off a bomb hidden in his underwear aboard a Northwest Airlines flight as it approached Detroit, Michigan, on December 25.

AbdulMutallab is alleged to have been carrying 80 grams of PETN in that attempted attack.

"The quantity of PETN in these [new] devices was about five times the volume used at Christmas" by AbdulMutallab, Col. Richard Kemp, the former chairman of the British government's Cobra Intelligence Group, told CNN affiliate ITN. The plot "does appear to be a typical al Qaeda-type operation," he said.

A source closely involved in the investigation said the detonating substance was Lead Azide. Lead Azide is a "very powerful initiator" which is easily prepared and is a standard substance in detonations, the source said.

American and British authorities said explosive devices jammed into ink toner cartridges were powerful enough to bring down a large aircraft.

Secretary of Homeland Security Janet Napolitano told CNN on Saturday that the plan to send the explosives has the "hallmarks of al Qaeda (in the Arabian Peninsula) -- they are constantly trying things to test our system."

The group is based in Yemen, a poor Arab nation that has emerged as a major operating base for al Qaeda and other terror groups.

Yemen has asked for outside help to thwart terror groups, but the country, the ancestral home of Osama bin Laden, is still used for operations, U.S. officials say.

Yemen's president said his country is cooperating with the U.S., the U.K., and Saudi Arabia.

"We acknowledge that we have a problem with terrorism, specifically the presence of al Qaeda, and we continue to pay a high price," Saleh said.

U.S. authorities were grateful for a tip from Yemen's oil-rich neighbor, Saudi Arabia, alerting them to the suspicious packages.

The Saudi government provided U.S. officials with tracking numbers of the two packages, enabling quick tracing to the United Kingdom and Dubai, a source told CNN.

President Obama called Saudi King Abdullah on Saturday to thank him, the White House said.

Obama counterterrorism advisor Brennan spoke to Saleh, stressing "the importance of close counterterrorism cooperation, including the need to work together on the ongoing investigation into the events over the past few days," according to the White House.

Over the past several months, Yemen, which wants to be seen as a committed partner in the fight against terrorism, has launched several offensives against al Qaeda in its country, but has not captured al-Awlaki.

Authorities, meanwhile, said the explosive devices were meticulously crafted.

They were "professionally" loaded and connected using an electric circuit to a mobile phone chip tucked in a printer, Dubai police told WAM, the official news agency for the United Arab Emirates. The devices were packed in printer toner cartridges and designed to be detonated by a cell phone, a source close to the investigation told CNN.

The package found at England's East Midlands Airport contained a "manipulated" toner cartridge and had white powder on it as well as wires and a circuit board, a law enforcement source said Friday. A similar package set to be shipped on a FedEx cargo plane was discovered in Dubai, officials there said.

When the Saudis warned British law enforcement that there were explosives inside the cartridge at East Midlands, the British -- using human and canines -- could not detect the material, according to a U.S. law enforcement official familiar with investigation.

The British authorities contacted the Saudis to verify the tip, the official said. The Saudis told them to inspect the cartridge again, and that is when the British authorities discovered the material, the official said.

In response to the threat, authorities stepped up searches Friday of cargo planes and trucks in several U.S. cities, said law enforcement sources with detailed knowledge of the investigation.

Also Friday, the Transportation Security Administration stopped all packages originating from Yemen, and shipping companies UPS, FedEx and DHL all said they were complying with the order.

Britain and Germany have also stepped up security measures around cargo originating in Yemen.

-- CNN's Jeanne Meserve, Mohammed Jamjoom, Susan Candiotti, Kathleen Johnston and Ross Levitt contributed to this report.

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