United States of Secrets, FRONTLINE’s two-part investigation of the National Security Agency’s surveillance activities post-9/11, has been honored with a Peabody Award for excellence in documentary filmmaking.

“With extensive, candid interviews from both critics and defenders, FRONTLINE provided a great public service, revealing in clear, comprehensible detail how the U.S. government in its post-9/11 zeal came to monitor and collect the communications of millions of people around the world – and here at home – and the lengths to which officials have gone to hide the massive surveillance from the public,” said today’s announcement on the Peabody Awards website.

Part One of United States of Secrets, from Michael Kirk, traced the secret political history of the U.S. government’s mass surveillance program. Part Two, from Martin Smith, examined how Silicon Valley feeds the NSA’s global surveillance dragnet.

“Our deep investigation into the government’s spying program post-9/11 required years of gathering information, interviews, evidence, documents and archival material. It’s indeed gratifying that it was judged worthy of the Peabody Award,” said Kirk, a veteran FRONTLINE producer, director and writer. “My team and I are grateful to the series and PBS for encouraging us to take on these important topics year in and year out.”

The award is Kirk’s second Peabody in as many years; his investigation into the NFL’s concussion crisis, League of Denial, won last year.

“I am honored along with my colleagues to be recognized by the Peabody board of jurors,” said Smith, also a veteran FRONTLINE producer, writer, and reporter who has won multiple Peabody Awards.

“In Privacy Lost, we endeavored to pierce the veil of secrecy surrounding the activities of the Silicon Valley companies that feed law enforcement and our national security state with daily torrents of information about our personal lives,” said Smith. “The program asked to what end and whether the appropriate balance between privacy and security has been forever lost. Edward Snowden opened the conversation. We worked to advance it.”

The winning teams of filmmakers aren’t resting on their laurels: Kirk’s next FRONTLINE documentary, Secrets, Politics and Torture, about the fight over the CIA’s controversial “enhanced interrogation” methods, premieres May 19. Smith’s next FRONTLINE film, Obama at War, premieres May 26 and will go inside the administration’s struggle to deal with ISIS and the deadly civil war in Syria.

“We’re honored to be trusted with the mission of producing in-depth investigative journalism on the issues that shape our times,” said David Fanning, FRONTLINE founder and executive producer. “We couldn’t do this work without our funders, PBS and CPB, and the viewers who watch and support our documentaries.”

“Everyone worked so hard to bring this comprehensive investigation to the public, and we’re very proud to receive this award,” said Raney Aronson-Rath, FRONTLINE deputy executive producer.

The Peabody Award for United States of Secrets will be presented on May 31. This is FRONTLINE’s seventeenth Peabody.

Watch the winning United States of Secrets films:

Part One: The Program

Part Two: Privacy Lost