2010 was an extraordinary difficult year for organized crime related violence in Mexico. The year was characterized by rapidly changing alliances between organized crime groups that contributed to making 2010 the most violent year yet, especially in terms of homicides connected to organized crime. The historic relationship between the Gulf organization and its enforcer wing – the Zetas – finally broke down resulting in open armed conflict. This development, in turn, resulted in new and renewed alliances, sometimes between former enemies. For example, the Gulf organization found itself working with its former rivals, the Familia Michoacana and the Sinaloa organization, against its former enforcer wing, the Zetas.

2010 was also characterized by a number of significant government-inflicted blows again major cartel leadership. The Beltrán Leyva Organization suffered the most series setbacks with the death of its principle leader, Arturo Beltrán Leyva, in December 2009 and the subsequent arrest of two others leaders including Carlos Beltán Leyva in January and U.S.-born Edgar "La Barbie" Valdez Villarreal in August. Government operations variously led by the Mexican Marines, Army, and Federal Police resulted in the deaths of organized crime leaders from the Gulf – Antonio Ezequiel Cárdenas Guillén AKA Tony Tormenta; Sinaloa – Igancio "Nacho" Colonel; La Familia Michoacana – Nazario Moreno; and the arrest of Eduardo Teodoro "El Teo" Garcia Simental amongst others.

While these were positive developments, homicide levels were also at an all time peak by the end of 2010 reaching an annual rate of just over 15,000, a 60% increase over 2009 rates. Nevertheless, there is also evidence offered by the Mexican government that homicide rates actually declined towards the end of the year. The Mexican Office of the Presidency has reported that a dramatic increase in homicide rates took place in the first two quarters of 2010, but this rate actually stabilized in the third quarter and declined by nearly 11% in the 4th quarter of the year according to government statistics.

There are several questions that emerge from this report. Is this a sustainable trend or simply a temporary, albeit welcome, reprieve. Second, is the decline in homicide rates the result of governmental policy or a reflection of one criminal organization gaining control over a disputed territory or rival organization? These are important questions that we will continue to analyze throughout 2011.

Below are links to interesting maps and data bases that help shed light on the evolving relationships between Mexican organized crime groups as well as data about the extent and geographic concentration of organized crime related homicides in 2010.