Cosmic Whistleblowers (2015) on Netflix

Plot summary

A filmmaker spends three years chasing answers to the Roswell incident of 1947, seeking out the witnesses to it who are still alive. The trail carries him to Washington, D.C., where he draws a line between the UFO question and the White House, and looks into efforts there to release classified documents from the era of the cover-up. During the filming, the Roswell researchers he follows are handed old picture slides that are said to be photographs of alien bodies taken from the crash site. Those researchers intend to show the material to a worldwide audience broadcast live from Mexico City, arguing that aliens came down at Roswell.