'The Tin Can People' by  Edward Bond

'It is now seventeen years after the nuclear holocaust. A group of survivors has formed a peaceful commune living off some warehouses filled with tin cans of food. A stranger is warmly welcomed into their midst, but when one of the group drops dead, the stranger is assumed to be contaminated. As the deaths multiply the group leader determines this intruder must be hunted down and killed. Thus the survivors, who seem to believe in old ideals, change when they feel threatened to barbity.'