The Huffman international Flying School, where two of the September 11th hyjackers trained, have just received letters from the INS (US Immigration Dept.) that their visa applications have been approved. The INS said that the original approval had been granted on 17 July and that the school had been notified in the summer. These letters were merely a “backup notification”. They blamed a backlog of paperwork at their processing centre in Kentucky for the delay. The papers relate to Mohammed Atta and Marwan Al-Shehhi. Atta is believed to have been the ring-leader of the group. He, along with three others, seized American Airlines Flight 11 from Boston-Los Angeles and flew it into the North Tower of the World Trade Center. Al-Shehhi is believed to have piloted United Airlines Flight 75, also from Boston-Los Angeles, into the South Tower 17 minutes later.