Ivan Cooper led an anti-internment march which developed into a massacre where how many people died ?
Ivan Cooper:  He is best known for leading an anti-internment march which developed into the Bloody Sunday massacre on 30 January 1972, in Derry, Northern Ireland. Bloody Sunday (1972):  Fourteen people died: thirteen were killed outright, while the death of another man four months later was attributed to his injuries.
Fourteen people died