The leader of an online group behind suspected US military document leaks is national guardsman Jack Teixeira, officials have told NBC News. Teixeira, 21, is said to have overseen a private online group, containing around 30 people, in which the leaked documents were shared. He is a member of the intelligence wing of the Massachusetts Air National Guard, according to interviews and documents reviewed by The New York Times. Officials told Sky News' US partner network, NBC News, that they have been on to him for some time and that an arrest is imminent. While their accuracy has been questioned,...