TheCoahuila mass graves was themass murder of 38 people near the city ofPiedras Negras,Coahuila,Mexico, on 3 June 2011.[1] The three clandestinemass graves where the bodies wereexhumed were found by theMexican military and authorized personnel after an anonymous call notified them of the location where the decaying bodies were. The investigators found buttons, shirts, coins, and watches.[2] The mass graves were purposely covered with soil and grass to simulate apasture.[3] All of the bodies were burned to death.[4]