Forty-nine dismembered bodies are discovered by Mexican authorities on Mexican Federal Highway 40.

The Cadereyta Jiménez massacre occurred on the Fed 40 on 12–13 May 2012. Mexican officials stated that 49 people were decapitated and mutilated by members of Los Zetas drug cartel and dumped by a roadside near the city of Monterrey in northern Mexico. The Blog del Narco, a blog that documents events and people of the Mexican Drug War anonymously, reported that the actual (unofficial) death toll may be more than 68 people. The bodies were found in the town of San Juan in the municipality of Cadereyta Jiménez, Nuevo León at about 4 a.m. on a non-toll highway leading to Reynosa, Tamaulipas. The forty-three men and six women killed had their heads, feet, and hands cut off, making their identification difficult. Those killed also bore signs of torture and were stuffed in plastic bags. The arrested suspects have indicated that the victims were Gulf Cartel members, but the Mexican authorities have not ruled out the possibility that they were U.S.-bound migrants. Four days before this incident, 18 people were found decapitated and dismembered near Mexico's second largest city, Guadalajara.The metropolitan area of Monterrey is an important warehousing center for cocaine, marijuana and other illegal drugs bound for U.S. consumers. The natural gas wells and pipelines running through Cadereyta and the U.S-Mexico border have also been the most tapped by thieves, supplying gasoline and other natural resources to Mexico's criminal underworld. Small towns, ranches, and isolated communities in Nuevo León have long been treasured by drug traffickers. The Mexican drug trafficking organizations have been fighting for the territorial control of the smuggling routes to the United States, and this massacre may be the "latest blow in an escalating war of intimidation among drug gangs." The cartels also fight for the control of local drug markets and extortion rackets, including shakedowns of migrants seeking to reach the United States. In addition, the discovery seems to echo several other mass murder events where the drug cartels have left large numbers of bodies in public places as warnings to their rivals. The authorities have blamed much of the violence on Los Zetas – a cartel originally set up by ex-commandos that deserted the Mexican Army in the 1990s – and the Sinaloa Cartel, an organization originally headed by Joaquín "El Chapo" Guzmán, once Mexico's most-wanted drug lord.