The US has dropped charges against Mohammed al-Qahtani, who allegedly planned to be the “20th hijacker” in the 9/11 attacks, Reuters reports. The US military tribunal at Guantanamo Bay rejected the charges against Qahtani “without prejudice,” meaning that the Saudi citizen may yet face prosecution. The charges against the other five alleged planners, including Khalid Sheikh Mohammed, were approved. (More September 11 stories.)