The 21-year-old National Guard airman was frantic as he joined a call with members of a small online gamer community that has improbably ended up at the centre of a federal investigation into a major U.S. security breach. It sounded as if the airman, Jack Teixeira, was in a speeding car, said a member of the group who uses the screen name Vahki. “Guys, it’s been good — I love you all,” Teixeira said, according to Vahki. “I never wanted it to get like this. I prayed to God that this would never happen. And I prayed and prayed and...