There, he'll instantly become one of the ten most notorious inmates at the facility, known for housing the worst of the worst. Below, see our countdown of the other nine, along with a brief summary of their heinous deeds.9. Zacarias Moussaoui. Often referred to as the twentieth hijacker, Moussaoui was accused of having been a replacement for any of the nineteen participants in the 9/11 attacks who could not fulfill their lethal duties. The French citizen was convicted of conspiracy, sentenced to life without parole, and sent to Supermax. Click to continue our Supermax countdown.