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 Cadereyta Jiménez 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 once headed by Joaquín "El Chapo" Guzmán, Mexico's one-time most-wanted drug lord.
Since 2011, Los Zetas and the Sinaloa cartel have emerged as the two main criminal syndicates in Mexico's drug war, with smaller gangs lining up on either side in a competition that now resembles a "full-scale war." A string of mass slayings have convulsed Mexico in 2011 and 2012. Many of them took place in northern states, where Los Zetas have waged a war against rival drug trafficking organizations for the control of the smuggling routes into the United States. The Los Zetas gang dates back to 1999, when deserters of the Mexican Army Special Forces joined the ranks of the Gulf Cartel. Nonetheless, the two organizations split in early 2010, and have fought for the control of the trafficking routes since then. The powerful Sinaloa Cartel, the Zetas' mortal rivals, has stood up and fought Los Zetas too. Since late April 2012, Los Zetas has been under immense pressure by the alliance between the Gulf cartel and the Sinaloa cartel. In March 2012, thirteen Los Zetas' members were killed and dismembered by the Sinaloa Cartel in a turf war; Los Zetas responded in kind, killing at least 10 members of the Sinaloa cartel in their rival's turf.
Much of the violence between Los Zetas and the Sinaloa cartel is the result of fighting over cocaine supplies from South America. On the supply side, the increased pressures on Sinaloa kingpin Joaquín Guzmán Loera, whose operations in Colombia in 2012 prompted his organization to grab larger shares of cocaine from Peru and Ecuador, threatened the supply-lines of Los Zetas, and triggered tit-for-tat attacks among both cartels. The Sinaloa cartel and Los Zetas are "regional and cultural opposites," because the Sinaloa organization has been moving drugs north from the ranch country parts in Mexico into the U.S. for generations, while Los Zetas are newer arrivals from the more urban eastern coast. In addition, Los Zetas is a transient cartel without real territory or a secure stream of income, while the Sinaloa Cartel has a lucrative cocaine trade and the control of smuggling routes and territories. But the former are heavily armed, while the latter's enforcement arm is weaker. The Sinaloa cartel uses tit-for-tat attacks as a way of bringing down the newcomers; for Los Zetas, it is about maintaining their violent reputation – the organization's most valued asset. Moreover, Los Zetas pose a bigger insurgency threat to the Mexican government than the older cartels in the country because of the brutality of their attacks against the security forces, their disregard for civilians' lives, and their dangerous habits that go beyond the "unspoken codes of older traffickers." The violent reputation of Los Zetas has made northeastern Mexico a no-go zone for many. Los Zetas, unlike the other traditional drug cartels, act like urban guerrillas; a police chief in Mexico explained how the Zetas would make anonymous phone calls to get the police out in the streets, block the road where the police were, and then open fire from all sides. In addition, the goal of Los Zetas differs greatly from other drug trafficking organizations in Mexico. Other cartels focus primarily in drug producing and drug trafficking, while Los Zetas often move into urban areas to diversify their criminal agenda and carry out a number of crimes. Their presence represents a new model for organized crime, unseating many older cartels with their brutal violent tactics that destabilize Mexico.
The drug violence in the state of Nuevo León and all across Mexico has left more than 50,000 people dead since President Felipe Calderón took office in 2006. His military-led approach shortly after taking office spiraled the violence in the country, and has eroded the support of Calderon's conservative National Action Party (PAN), which did not regain the presidential seat in the 2012 presidential elections. The city of Monterrey was long been a bastion of the PAN, and the local business community has been "livid" about the violence in their city. Surveys showed that voters thought that the Institutional Revolutionary Party (PRI), which ruled Mexico uninterruptedly from 1929 to 2000, is likely to control and put down the violence. Its 71-year rule was "tainted by corruption," and critics have accused the PRI of making deals with the cartels to maintain peace in the country.
In the 1990s, the drug cartels in Mexico did not cut off the heads of the victims. Instead, they used different "codes of murder" established between the mafias. A bullet through the back of the head, for example, signified that the victim was a traitor; a bullet through the temple, however, signified that the victim was member of a rival drug gang. Now, decapitation is a tactic often used by the criminal organizations in Mexico—primarily by Los Zetas and its two main rivals, the Gulf and Sinaloa cartels. The first public decapitation was carried out by La Familia Michoacana in September 2006, when several gunmen opened the doors of a bar in the Mexican state of Michoacán and threw five severed heads on the dance floor. The practices of beheading victims in Mexico is believed to have come from Guatemala in the year 2000, when Los Zetas extended their criminal network into Central America and eventually incorporated with the elite jungle military squad known as the Kaibiles. The Kaibiles had been trained to intimidate the local population with beheadings during the Guatemalan Civil War (1960–1996). Others see the link with the religious cult of the Santa Muerte ("Holy Death"). Wherever it stems from, decapitations is "now a staple in the lexicon of violence" in the Mexican drug war.