leader of al-qaeda, ayman al-zawahri. in an online video message, he threatens "the gravest consequences" if the surviving boston marathon bomber is executed. dzhokhar tsarnaev was sentenced last year to death by lethal injection. the 2013 bombing killed three people. u.s. attorney general loretta lynch voiced regret today about a meeting earlier this week with former president bill clinton. they spoke monday, for about 30 minutes, after his private plane landed near her government aircraft at the phoenix airport. it stoked criticism because the f.b.i. is investigating hillary clinton's e-mail practices as secretary of state. today, in aspen, colorado, lynch repeated that she and the former president never discussed the investigation, but she understands the criticism. >> i may have viewed it in a certain light, but the issue is, how does it impact the work that i do and the work that the department of justice does? and i certainly wouldn't do it again, because i think it has cast a shadow over what it should not, what it will not touch. >> woodruff: lynch also said she plans to accept w

ayman al-zawahiri were terribly impressed with him. he seemed and acted like a thug. he was not very sophisticated. in fact, they considered him a rather poor recruit to al-qaeda. >> narrator: zarqawi would leave kandahar determined to continue jihad, and to prove bin laden wrong. in 2002, he saw his chance. as president bush signaled saddam hussein had to go, zarqawi moved to a terrorist camp in northern iraq. it set off alarm bells at the cia. cia operations officer sam faddis, who ran a kill/capture team, was assigned the case. >> headquarters is extremely, extremely interested. i mean, the number one time-sensitive priority, as of june '02, when i left headquarters, was go collect on this islamic extremist enclave along the iran/iraq border. >> narrator: it didn't take long for faddis to find zarqawi and learn what was going on in the camp. >> we literally had guys that were working for us that were inside the camp. they're working on chemical and biological weapons. they were doing a lot of work with cyanide-based things. >> narrator: at cia headquarters, it was a threat they co