El Tio... you broke my heart you ######... pay back's a b-tch!
Apologies for the outburst... Let's just move past that and begin the hunt.
First you need to find the 3 Graves. Use a small Heli to save you lots of time. You find these grave is the Ancient Cemetery of Miners (Image 1) Once you have found them, 'Read' Newspaper on Graves by interacting with them (press 'E'). They are the Graves with Lit Candles (Image 3) burning on them and vultures flying above them. Thermal Vision Can assist with this. Here are the locations:
-19.6640 / 64.0318 (Image 2)
-19.6248 / 64