(CNN) -- The explosive found hidden in a package on a plane in the United Arab Emirates on Friday may have traveled on passenger planes to get there, airline officials said Sunday.

The explosive, along with a similar device found in the United Kingdom, appear to have been designed to detonate on their own, without someone having to set them off, the top White House counterterrorism official told CNN.

"It is my understanding that these devices did not need somebody to detonate them," said John Brennan, President Barack Obama's assistant for homeland security and counterterrorism.

U.S. investigators believe al Qaeda bomb maker Ibrahim Hassan al-Asiri, 28, is linked to that package and another one found on a second airplane in Britain's East Midlands Airport on Friday, a federal official, who was briefed by authorities, told CNN Sunday. Both packages were addressed to synagogues in Chicago, Illinois.

Al-Asiri, who is thought to be in Yemen, is a Saudi who was high on Saudi Arabia's list of most wanted published in February 2009. He is also believed to be the bomber who designed last year's failed Christmas Day underwear bomb.

Separately, an engineering student arrested in Yemen was released Sunday, along with her mother, according to her father, Mohammed Al-Samawi. She was earlier identified as Hanan Al-Samawi, a fifth-year student at Sanaa University in the Yemeni capital, said Abdul-Rahman Barman, a human rights attorney and activist who said he was asked to represent her.

A high-level source in the United Arab Emirates said Hanan Al-Samawi's name was found on the cargo manifest of the device found in Dubai.

Answer the following questions:
1. who is linked to the package?
2. where was the plane that the device was on?
3. was there another similar device found?
4. where?
5. whose name was found on the cargo manifest?
6. did the device travel on passenger planes?
7. how old is Hassan?
8. where is he thought to be?
9. did the device need anyone to detonate it?
10. who in Obama's administration said this?
11. who is he?
12. where is Hassan a national of?
13. what day was Hanan released?
14. which airport in Britain was the package at?
15. who were the packages addressed to?
16. who was asked to represnt Hanan?
17. which other bomb had Hassan designed?
18. was Hanan in school?
19. studying what?
20. which city in UAE found the packages?
1. Hassan al-Asiri
2. the United Arab Emirates
3. Yes
4. the United Kingdom
5. Hanan Al-Samawi
6. It may have.
7. 28
8. Yemen.
9. No
10. John Brennan
11. Assistant for homeland security and counterterrorism.
12. Saudi Arabia
13. Sunday
14. East Midlands Airport
15. to synagogues
16. Abdul-Rahman Barman
17. last year's Christmas Day underwear bomb.
18. Yes
19. Engineering
20. Dubai.