US prosecutors have reached a plea deal with 9/11 mastermind Khalid Sheikh Mohammed to avoid a death penalty trial. The deal also includes Walid bin Attash and Mustafa al-Hawsawi, who will plead guilty to conspiracy. This move brings a resolution to their long-running cases held at Guantanamo Bay, which was used to detain militants captured during the 'War on Terror' after 9/11.