A Libyan rebel points his rifle at a man accused of being a mercenary fighting for Muammar Gaddafi. Many have been arrested and accused of fighting for dictator, but claim they were press-ganged. Earlier this year, as revolution and siege ground Tripoli to a halt, Mehdi Hassan knew where to look for work. He would drive his taxi to a roundabout in the south-west of the capital and wait for foreigners...