The Guardian has geolocated eyewitness accounts of the capture of the Sudanese city of El Fasher by the paramilitary Rapid Support Forces group and the ethnically-targeted massacres that took place in the immediate aftermath. Journalists are unable to access the area and have limited access to information. Guardian reporter Kaamil Ahmed explains how - when combined with satellite imagery and videos posted by RSF fighters - the testimonies provide us with the clearest picture yet of the horrific events that unfolded