'Citizenfour'

In January 2013, filmmaker Laura Poitras received an encrypted email from a person calling himself Citizenfour. He promised to deliver shocking information about the degree to which the federal government was spying on American citizens. In her film, Citizenfour, Poitras reads from those early emails which came, as the world now knows, from Edward Snowden.

Snowden had chosen to contact Poitras -- who lives in Berlin because of Germany's strong privacy laws -- because of her previous work and her interest in domestic surveillance. She had been been a target of it herself.

After months of secret correspondence with Snowden, Poitras flew to Hong Kong in May. 2013 to meet him. Citizenfour focuses largely on Snowden's tense days in a hotel room there, as he told his story to reporters Glenn Greenwald and Ewen MacAskill and became world-famous virtually overnight.

Kim Masters talks to Poitras about the process of making Citizenfour and her earlier film, My Country, My Country, including how she got funding for both projects. They also discuss possible reasons Poitras was stopped and searched at the US border so many times, a mystery that remains unsolved to this day.