Gul Zaheer was a gaoler in Afghanistan in 1842 during the First Afghan War. He was a sadistic man who enjoyed torturing his prisoners.
Ian Chesterton and Lieutenant Symonds were prisoners in Zaheer's jail. Zaheer forced them into a tug of war in which the winner would pull the loser into a pit filled with carnivorous animals.
When Ian and Symonds refused to fight each other, Zaheer shoved Symonds into the pit, killing him. He was about to do the same to Ian, but was interrupted by the arrival of the First Doctor with several armed soldiers, who overpowered Zaheer's men. Ian, acting on instinct, shoved Zaheer into the pit, killing him. (PROSE: Mire and Clay)