February 19 – At least 44 people are killed in a prison brawl in Apodaca, Nuevo León. The brawl is believed to have been started after the Gulf Cartel and Los Zetas, two rival Mexican drug cartels, clashed inside the prison.[4]
April
April 29 – Seven people are killed in a three-way shootout between rival drug cartels and the authorities in the Mexican state of Sinaloa.[5]
May
May 2 – A gunfight between the Mexican Army and suspected gunmen of a drug cartel left 12 dead in the state of Sinaloa.[6]
23 bodies—14 of them decapitated and 9 of them hanged from a bridge—are found in the Mexican city of Nuevo Laredo; those killed were reportedly members of the Gulf Cartel who were killed by Los Zetas, a rival cartel.[7]
Three journalists are killed and their bodies dumped in plastic bags in a canal in Boca del Río in the Mexican state of Veracruz, where the rival criminal groups of Los Zetas and the Gulf Cartel are fighting for territorial control.[8]
May 9 – 15 mutilated bodies are found inside two abandoned SUVs in the state of Jalisco, a region that is under dispute between Los Zetas and the Sinaloa Cartel. The Mexican authorities believe the massacre is a response by Los Zetas for the 2012 Nuevo Laredo massacres reportedly carried out by Joaquín Guzmán Loera (a.k.a. El Chapo).[9]
June
June 5 – The dismembered remains of 7 bodies are found in the Mexican state of Sinaloa. The bodies are discovered along with a written message accusing the authorities of cooperating with the Sinaloa Cartel, suggesting that the message may have been written by Los Zetas.[10]
June 25 – Alleged drug traffickers shoot and kill 3 policemen who were on an anti-narcotics operative inside the Mexico City International Airport. The assassins were wearing law enforcement uniforms, although the Mexican authorities said that the cartel members sometimes wear false uniforms. No suspects have been arrested.[11]
June 29 – A car bomb explodes outside the city hall in the Mexican border city of Nuevo Laredo, injuring 7 bystanders. This is the third car bomb in Nuevo Laredo this year, and much of the violence is blamed on the country's most powerful cartels: Los Zetas and the Sinaloa Cartel.[12]
July
July 5 – A high-ranking drug boss in the Mexican criminal group known as Gulf Cartel is apprehended in Costa Rica.[13]
July 9 –
Ten decapitated bodies are discovered inside an abandoned vehicle along a roadside in the Mexican city of Torreón, Coahuila. Reportedly, a written message was left behind by the perpetrators.[14]
A gunbattle breaks out near Choix, Sinaloa, after alleged drug traffickers ambushed and killed seven police officers; upon the aggression, the officers gunned down four cartel members.[15]
The FBI reveals that the Los Zetas laundered millions of dollars through accounts at Bank of America; that money was then used to finance a horse racing business in the United States, allegedly ran by José Treviño Morales.[16]
August
August 1 – Prosecutors formally charge three Mexican Army generals, including active General Roberto Dawe Gonzalez and retired General Tomás Ángeles Dauahare, and a lieutenant-colonel for their alleged links to a drug trafficking organization known as the Beltrán-Leyva Cartel.[17]
August 3 – The Mexican Army arrests another member of Los Zetas cartel responsible for decapitating 49 bodies and dumping them on a roadside in May 2012; the suspect is one of the 37 fugitives of the Apodaca prison riot earlier this year.[13]
Cartel members armed with AK-47 assault rifles gun down and kill five teenage boys in Escobedo, Nuevo León.[13]
August 6 – Alleged members of Los Zetas cartel attack several media outlets in Monterrey for publishing on a rumored split between the two principal Zetas bosses.[19]
August 10 – Four suspected drug traffickers of the Sinaloa Cartel, including the cousin of Joaquín "El Chapo" Guzmán, Mexico's most-wanted drug lord, are captured in Spain.[20]
September 1 – Eduardo Arellano Félix, a former drug lord of the Tijuana Cartel, is extradited to the United States from Mexico. He is the last brother of the cartel in a 2003 indictment to be extradited.[22]
