Q: In this task, you are given a set of context paragraph and some supporting facts to answer a question. Your task is to generate answer for given question based on set of context paragraphs and supporting facts.
Context_1 : Juan Carlos Garcia Sancho Orozco (born November 10, 1994 in Tepic, Nayarit), known as Juan Garcia Sancho, is a professional Mexican footballer who currently plays for Cruz Azul. Context_2 : Juan Garcia Hortelano (19281992) was a Spanish writer. He was born in Madrid on Valentine's Day 1928. His father was a doctor. When the Spanish Civil War broke out, he was sent with his siblings to Cuenca, only returning to Madrid in 1937 where he lived with his maternal grandparents. The libraries at school and home turned him into an avid reader. Following the war, he entered college in 1941, later studying law at Madrid University. He joined the Civil Service in 1953. Throughout his life, he dedicated himself to writing with fervour and discipline without abandoning his administrative job in Madrid. He cultivated friendships with writers and intellectuals of his generation: Juan Benet, Carlos Barral, Jaime Gil de Biedma, Juan Marse and Angel Gonzalez. Context_3 : The Aggi Crew were a criminal drug gang based in the St Paul's district of Bristol. The name of the gang was taken from the surnames of the founding gang members. The gang dominated the city's drug market throughout most of the 1990s, until in 1998 six gang members were jailed after being caught with more than a 1 million worth of crack cocaine. Context_4 : Osiel Cardenas Guillen (born May 18, 1967) is a former Mexican drug lord and the former leader of the Gulf Cartel (Spanish: "Cartel del Golfo" ) and Los Zetas. Originally a mechanic in Matamoros, Tamaulipas, where he was born, he entered the Gulf Cartel by helping Juan Garcia Abrego, the capo at the time; when Garcia Abrego was arrested in 1996, some infighting erupted within the cartel. Osiel Cardenas eventually took control by killing his friend and contender Salvador Gomez, earning Cardenas the nickname ""El Mata Amigos"" (The Friend-Killer). Context_5 : Juan Garcia Abrego (born September 13, 1944) is a former Mexican drug lord who started out his criminal career under the tutelage of his uncle Juan Nepomuceno Guerra, who is reported to be the former head of a criminal dynasty along the U.S.-Mexico border now called the Gulf Cartel. Context_6 : Christopher Michael Coke, also known as Dudus (born 13 March 1969), is a Jamaican drug lord and the leader of the Shower Posse, a violent drug gang started by his father Lester Coke in Jamaica, which exported "large quantities" of marijuana and cocaine into the United States. Context_7 : Juan Garcia Lorenzana, known as Juanin Garcia, (born 28 August 1977, in Leon) is a Spanish handball player. He currently plays for Barcelona, with whom he won the Champions League in 2011 in the finale against Ciudad Real. Context_8 : Maria de los Angeles Pineda Villa is the former first lady of Iguala, a city in Guerrero, Mexico. Pineda Villa and her husband, Jose Luis Abarca Velazquez were accused by Attorney General of Mexico Jesus Murillo Karam of the "probable masterminds" behind the 2014 Iguala mass kidnapping and disappearance of 43 students from the Ayotzinapa Rural Teachers' College. Pineda Villa and her husband fled hours after the reported abductions and were arrested by federal authorities on November 4, 2014. The prosecution's investigation indicates that Mayor Abarca ordered local police to stop the students from protesting a political event and speech Pineda Villa was scheduled to hold. The police allegedly attacked the students' buses when they entered Iguala and then delivered them to members of the local drug gang, Guerreros Unidos. Along with her familial ties to the Sinaloa Cartel and Beltran-Leyva Cartel, confessions by detained gang members and police officers have revealed Pineda Villa as the "principle operator" of the Guerreros Unidos. Context_9 : The Altamira prison brawl was a deadly fight that occurred on 4 January 2012 in Altamira, Tamaulipas, Mexico. Officials from the state of Tamaulipas confirmed that 31 people were killed, with another thirteen injured. The fight started after a drug gang burst into a section of the prison where they were banned from, attacking their rival gang housed there, triggering the fight. During the altercation, the inmates used several kinds of white arms to kill their opponents. The prisoners also used sticks and knives to massacre the members of the rival gang. Context_10 : Juan Nepomuceno Guerra Cardenas (July 18, 1915 July 12, 2001) was a Mexican crime lord, bootlegger, businessman and smuggler who founded the Gulf Cartel, a drug trafficking organization. He is often considered the "godfather" of U.S-Mexico border cartels. fact_1 : Juan Garcia Abrego (born September 13, 1944) is a former Mexican drug lord who started out his criminal career under the tutelage of his uncle Juan Nepomuceno Guerra, who is reported to be the former head of a criminal dynasty along the U.S.-Mexico border now called the Gulf Cartel. fact_2 : Juan Nepomuceno Guerra Cardenas (July 18, 1915 July 12, 2001) was a Mexican crime lord, bootlegger, businessman and smuggler who founded the Gulf Cartel, a drug trafficking organization. Question: Juan Garcia Abrego was the nephew of the founder of what drug gang?
A:
Gulf Cartel