major funding is provided by the john d. and catherine t. macarthur foundation, committed to building a more just, verdant, and peaceful world. and by reva and david logan, committed to investigative journalism as the guardian of the public interest. additional funding is provided by the park foundation, dedicated to heightening public awareness of critical issues. and by the frontline journalism fund. ( helicopter blades whirring ) >> tonight, i can report to the american people and to the world that the united states has conducted an operation that killed osama bin laden, the leader of al qaeda, and a terrorist who's responsible for the murder of thousands of innocent men, women, and children. ( cheering ) ( explosion ) >> go, go, go, go, go! >> narrator: on may 2, 2011, us special operations forces killed the world's most wanted man in a raid on a house in pakistan. the operation gave the world a glimpse into a vast and secret campaign being waged by the united states. it's known as the kill/capture program. >> all right, spot on 1-6-0. ( explosion

major funding is provided by the john d. and catherine t. macarthur foundation. committed to building a more just, verdant, and peaceful world. and by reva and david logan. committed to investigative journalism as the guardian of the public interest. additional funding is provided by the park foundation. dedicated to heightening public awareness of critical issues. and by the frontline journalism fund with a grant from scott nathan and laura debonis. >> narrator: july 1997, the naval station in norfolk, virginia. a sailor, william bosko, had just returned from sea. eager to see his new wife, he rushed home to this apartment complex. what he found inside horrified him. he ran next door to his neighbor, danial williams. >> william bosko came over, beating on my door, yelling frantically that his wife was dead. and i grabbed my phone, called 9-1-1, and went to see what... how i could help. >> you are clear. 8-8-14, clear. >> narrator: the police arrived minutes later. there was no forced entry. the apartment was clean and tidy, except for the bedroom, where michelle

major funding is provided by the john d. and catherine t. macarthur foundation. committed to building a more just, verdant, and peaceful world. and by reva and david logan. committed to investigative journalism as the guardian of the public interest. additional funding is provided by the park foundation. dedicated to heightening public awareness of critical issues. and by the frontline journalism fund. >> smith: in late 2009, an army intelligence analyst stationed in eastern iraq logged onto a classified server. >> you see all those people standing down there? >> that's a weapon. >> yeah. >> smith: he opened a file that had been flagged by army lawyers. >> ...have five to six individuals with ak-47s. request permission to engage. >> smith: it was footage taken from a us army helicopter gunship. >> light them all up. >> come on, fire. ( machine gun fire ) >> hey, roger! ( machine gun fire ) >> keep shooting. ( machine gun fire ) >> keep shooting. ( machine gun fire ) >> all right, we just engaged all eight individuals. >> oh, yeah. look at all those dead bastards.

major funding is provided by the john d. and catherine t. macarthur foundation. committed to building a more just, verdant, and peaceful world. and by reva and david logan. committed to investigative journalism as the guardian of the public interest. additional funding is provided by the park foundation. dedicated to heightening public awareness of critical issues. and by the frontline journalism fund, supporting investigative reporting and enterprise journalism. additional funding for frontline's expanded broadcast season is provided by the bill and melinda gates foundation. ( cheers and applause ) >> montgomery: san francisco's cow palace has hosted everything from rodeos to revival meetings. but last summer, it was home to something completely different-- a trade show for marijuana. when i first began covering this story, marijuana was on the verge of becoming legal here in california. inside, it already seemed pretty legal to me. >> the coolest mug in the city, right here. >> montgomery: everything was on offer-- pot smoothies, pot cookies, every known device

and catherine t. macarthur foundation. and union bank. >> union bank has put its financial strength to work for a wide range of companies, from smain blls esus major corporations. what can we do for you? >> "bbc world news" was pres