A top Pentagon official has attacked this week's widely watched congressional hearing on UFOs, calling the claims “insulting” to employees who are investigating sightings and accusing a key witness of not cooperating with the official US government investigation. Dr. Sean Kirkpatrick's letter, published on his personal LinkedIn page and circulated Friday across social media, criticises much of the testimony from a retired Air Force intelligence officer that energised believers in extraterrestrial life and produced headlines around the world.