Mexican forensic experts have identified all 16 Guatemalans whose bodies were found shot and burnt near the US border last month, prosecutors said Thursday. The massacre and attempted cover-up is alleged to have been carried out by cartel hitmen and corrupt police. The corpses of the Guatemalans, believed to be undocumented migrants, were found along with three dead Mexicans in a bullet-riddled pick-up truck in the northern state of Tamaulipas. Twelve police officers and eight immigration agents have been arrested on suspicion of involvement. At least one of the dead Mexicans is believed to have been involved in people-trafficking, according to the authorities. The Tamaulipas prosecutor's office said it had held a meeting with Guatemalan officials including Ambassador Mario Bucaro Flores to discuss the repatriation of the bodies "in a dignified manner." Tamaulipas, on Mexico's Gulf coast, is the shortest route to the US but migrants risk kidnapping, extortion and murder by gangs, as well as being caught up in cartel turf wars. In August 2010, 72 undocumented migrants were killed elsewhere in Tamaulipas in an attack blamed on the Zetas cartel. str/jla/dr/dw