Many of the human casualties in the arena were convicted criminals, forced to fight to the death with savage animals. This detail of the Roman-period Zliten mosaic from Tripolitania (modern day Libya) depicts two naked, defenseless criminals. One is being dragged into the ring. The other tries to separate the chained bull and bear that are fighting each other. Convicted criminals could also be crucified, burned to death or forced to kill others in staged combats. Author Donald Kyle argues that such humiliating and agonizing punishments served as a deterrent to future crime and deviance.