A tip off from a former secret police officer have led residents in the rebel-held town of Derna in eastern Libya to unravel secrets that were hidden by Muammar Gaddafi's regime for decades.<br /><br />A mass grave has been discovered in the area, and forensic doctors have found pieces of bone and clothing.<br /><br />They fear there are as many as seven people buried there.<br /><br />Al Jazeera's Sue Turton reports from Derna.
