As the drug trade expanded in Michoacán, the Gulf Cartel authorized a new enforcer group called Los Zetas in 2003.

This collaboration led to various drug-related crimes in Michoacán, including a 2004 prison break in Apatzingán to free members of the Gulf and Zetas cartels.

Following a plan initiated by his predecessor Vicente Fox, President Felipe Calderón deployed 4,000 troops to Michoacán on December 12 to combat the escalating drug-related violence that had claimed over 500 lives.

[3] Operation Michoacán is the first stage of the so-called War Against Drug Trafficking implemented by the federal government of President Felipe Calderón.

The joint operation has been questioned about the human rights violations that may have occurred, given the military presence among the civilian population of the state of Michoacán.