In September 2005, British special operations forces found themselves facing a problem.

Two of their own had been captured and beaten by local Iraqi police during an undercover operation in Basra, and their lives were hanging by a thread.

The operators were members of the famed Special Air Service (SAS) — the British equivalent of the U.S. Army’s Delta Force — and had been part of a surveillance operation targeting the police and their commander, suspected of rampant corruption.

Coalition intelligence also suspected the Iraqi police chief was working with insurgents, particularly the brutal Mahdi Army, a Shia militia organization supported by Iran.