Question: which Mexican drug cartel does its member murdered John Clay Walker 
Context: Heriberto Lazcano Lazcano (25 December 1974 – 7 October 2012), commonly referred to by his aliases Z-3 and El Lazca, was a Mexican drug lord and the leader of Los Zetas drug cartel.  He was one of the most-wanted Mexican drug lords. John Clay Walker (October 5, 1948 - January 30, 1985) was an American journalist and aspiring novelist who was abducted, tortured and murdered in Mexico by members of the Guadalajara Cartel under orders of their leader Rafael Caro Quintero.  Caro Quintero suspected Walker of working as an undercover U.S. Drug Enforcement Agent (DEA) while he lived in Guadalajara, Jalisco. The Cadereyta Jiménez massacre occurred on the Mexican Federal Highway 40 on 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 Beltrán-Leyva Cartel (also known as the Beltrán Leyva Organization (BLO); Spanish: "Cártel de los Beltrán Leyva" ("CBL")) was a Mexican drug cartel and organized crime syndicate, headed by the five Beltrán Leyva brothers: Marcos Arturo, Carlos, Alfredo, Mario Alberto and Héctor.  Founded as a branch of the Sinaloa Cartel, the Beltrán Leyva cartel was responsible for transportation and wholesaling of cocaine, heroin and marijuana (and the production of the last two).  It controlled numerous drug trafficking corridors, and engaged in human smuggling, money laundering, extortion, kidnapping, murder and gun-running. Servando Gómez Martínez (born February 6, 1966), commonly referred to by his alias La Tuta (The Teacher) for once being a teacher, is a Mexican drug lord and former leader of the Knights Templar Cartel, a criminal organization based in the state of Michoacán.  He is a former leader and founder member of La Familia Michoacana drug cartel, the split-off group of the Knights Templar.  On February 27, 2015, he was arrested by Mexican security forces in Morelia, Michoacán. The Tijuana Cartel (Spanish: "Cártel de Tijuana") or Arellano-Félix Organization (Spanish: "Cártel Arellano Félix - CAF") is a Mexican drug cartel based in Tijuana.  The cartel once was described as "one of the biggest and most violent criminal groups in Mexico."  However, since the 2006 Sinaloa Cartel incursion in Baja California and the fall of the Arellano-Félix brothers, the Tijuana Cartel had been reduced to few cells.  In 2016, the organization has become known as Cartel Tijuana Nueva Generación (New Generation Tijuana Cartel) and has begun to aligin itself under the Jalisco New Generation Cartel, along with Beltrán Leyva Organization (BLO) to create an anti-Sinaloa alliance, in which the Jalisco New Generation Cartel heads, creating a possible powershift in Mexico. The Guadalajara Cartel (Spanish: "Cártel de Guadalajara" ) was a Mexican drug cartel which was formed in the 1980s by Rafael Caro Quintero, Miguel Ángel Félix Gallardo and Ernesto Fonseca Carrillo in order to ship heroin and marijuana to the United States.  Among the first of the Mexican drug trafficking groups to work with the Colombian cocaine mafias, the Guadalajara cartel prospered from the cocaine trade. Clay Walker is an American country music artist.  His discography comprises nine studio albums and a greatest hits album, as well as 31 singles. Walker's first four studio albums — "Clay Walker", "If I Could Make a Living", "Hypnotize the Moon" and "Rumor Has It" — are all certified platinum by the RIAA, and his greatest hits album and "Live, Laugh, Love" are each certified gold by the RIAA.  "Clay Walker" is also certified platinum by the CRIA, while "If I Could Make a Living" and "Hypnotize the Moon" are certified gold. The Juárez Cartel (Spanish: "Cártel de Juárez"), also known as the Vicente Carrillo Fuentes Organization, is a Mexican drug cartel based in Ciudad Juárez, Chihuahua, across the U.S.-Mexico border from El Paso, Texas.  The cartel is one of several drug trafficking organizations that have been known to decapitate their rivals, mutilate their corpses and dump them in public places to instill fear not only into the general public, but also into local law enforcement and their rivals, the Sinaloa Cartel.  The Juárez Cartel has an armed wing known as La Línea, a Juarez street gang that usually performs the executions.  It also uses the Barrio Azteca gang to attack its enemies. The Medellín Cartel was a ruthless, highly organized and much-feared Colombian drug cartel originating in the city of Medellín, Colombia.  The drug cartel operated throughout the 1970s and 1980s in Bolivia, Colombia, Central America, Peru, and the United States, as well as in Canada and Europe.  It was founded and run by Ochoa Vázquez brothers Jorge Luis, Juan David, and Fabio, together with Pablo Escobar, George Jung, Carlos Lehder and José Gonzalo Rodríguez Gacha.  By 1993, the resistance group, Los Pepes (or PEPES), controlled by the Cali Cartel, and the Colombian government, in collaboration with the Cali Cartel, right-wing paramilitary groups, and the United States government, had dismantled the Medellín Cartel by imprisoning or assassinating its members.
Answer: The Guadalajara Cartel