Mexican police arrested the reputed head of a Sinaloa drug cartel assassination ring who is accused of plotting a massacre at a drug rehabilitation center. Federal police arrested Jose Antonio Torres Marrufo, identified as leader of the criminal organization known as "New People," the armed wing of the Sinaloa cartel led by Joaquin Guzman Loera, Mexico's Public Security Secretariat said in a statement on Saturday. Torres, 33, was wanted by the Mexican authorities, which offered a $150,000 reward for his capture, and the US justice system, which accuses him of drug trafficking. Torres allegedly masterminded the murder of 18 people at a drug rehabilitation center in Ciudad Juarez on September 2, 2009 in what appeared to be a turf battle among drug gangs. Juarez, which is considered the most violent city in Mexico, is a short walk across the border from El Paso, Texas. Torres allegedly coordinated activities of murderers hired by gangs that called themselves the "Murder Artists" and the "Mexicles," according to Mexican police. The Mexicles are rivals of the Barrio Azteca and the Aztecs gangs linked to the Juarez drug cartel, Mexican police said. The Juarez cartel sometimes had disputes with the much larger and powerful Sinaloa cartel for control of drug routes into the United States. "The capture of Torres means a strong blow to the criminal structure" of the Sinaloa cartel, the statement said. The arrest occurred in the central Mexican state of Guanajuato, where Torres is accused of coordinating operations of the "New People" assassins. Torres was arrested less than two weeks after another blow to the Sinaloa cartel's leadership. On January 20, the Mexican military shot and killed a top Sinaloa lieutenant named Luis Alberto Cabrera in an air strike. His boss, "Shorty" Guzman, is the most wanted drug trafficker by authorities in both Mexico and the United States. Forbes magazine has listed him as one of the most powerful men in the world with a personal fortune estimated at $1 billion.