Exclusive: 'Dumb mistake' exposed Iranian hand behind fake Proud Boys U.S. election emails - sources

Government analysts and private sector investigators were able to rapidly attribute to Iranian hackers a wave of thousands of threatening emails aimed at U.S. voters because of mistakes made in a video attached to some of the messages, according to four people familiar with the matter. "Either they made a dumb mistake or wanted to get caught," said a senior U.S. government official, who asked not to be identified.