Pisagua's remote location has led to it being used as a concentration camp on several occasions. It was most notoriously used as a prison camp and torture centre after Pinochet took power in the 1973 military coup, a number of political prisoners were executed in 1973 and 1974. On 2nd June 1990, after an investigation by human rights organisations, 20 bodies were found in a mass grave at the northern end of the old cemetery just outside Pisagua. The whereabouts of the bodies of several other prisoners who were in the camp and disappeared has never been discovered.