Complex sentence: He was detained in solitary confinement for six years at the Naval Consolidated Brig at Charleston, South Carolina, the only non-citizen known to have been held as an enemy combatant within the continental United States since the September 11 attacks.
Split into simpler sentences: He was detained in solitary confinement for six years at a Naval brig at Charleston, South Carolina. Al-Marri is the only non-citizen known to have been held as an enemy combatant within the continental United States since the September 11 attacks.