Fargo – With notorious drug trafficker Joaquin "El Chapo" Guzman now behind bars in New York after he was extradited from Mexico last month, federal prosecutors in North Dakota have their sights set on bringing one of his organisation's one-time rivals to the United States to face charges.In court documents unsealed on Tuesday, authorities say Juan Francisco Sillas-Rocha was a top lieutenant for the Arellano Felix cartel, which smuggled cocaine, marijuana and other drugs into the United States and competed against the Sinaloa cartel led by Guzman, once considered the most wanted man in the world.Authorities have described Sillas-Rocha as a prolific hitman responsible for killing 20 to 30 people a month during the cartel's heyday in Tijuana.Sillas-Rocha was arrested six years ago in Mexico, but his federal case in the US had remained sealed from public view until this week.Tim Heaphy, former US attorney from Virginia, said it's common to seal such cases to preserve an investigation and protect witnesses. Those fears tend to evaporate when a defendant is in custody for a long time.Conspiracy to commit murderUS Attorney Christopher Myers, the lead prosecutor, declined to comment on the case. Court documents in Mexico listed no attorney of record for Sillas-Rocha.Sillas-Rocha, known as "Ruedas", or "Wheels", is charged with three counts, including conspiracy to commit murder for a continuing criminal enterprise. He has been fighting extradition to North Dakota, where federal officials a decade ago began gathering incriminating evidence on the Arellano Felix cartel after one of its members killed a Minnesota man over a drug debt.Sillas-Rocha was arrested in Mexico in November 2011 and paraded in front of reporters by police in riot gear and masks. He remains in jail there.The case wound up in North Dakota after Jorge "Sneaky" Arandas, a member of the Arellano Felix gang, set up shop in the Red River Valley of North Dakota and Minnesota.Investigators say Arandas ordered the killing of Lee Avila, of East Grand Forks, Minnesota, in June 2005 for failing to pay for 2.3kg of methamphetamine that Arandas originally received from Sillas-Rocha.Arandas told police he feared that he would be killed for not paying Sillas-Rocha, so he had Avila murdered to show strength.Ordered to kill an entire familyThe indictment filed against Sillas-Rocha in March 2011 said that in addition to drug trafficking, Sillas-Rocha was involved in the supervision of crews that "participated in murder, attempted murder, kidnapping, human trafficking, public corruption of government officials, money laundering and other illegal conduct" meant to make money for the cartel.The document accuses Sillas-Rocha of attempting to arrange the killings of two California residents. He allegedly offered a San Diego street gang $25 000 to kill them, paying $4 000 in advance.When the gang couldn't find his targets, Sillas-Rocha upped his offer to $50 000 if the killings could be done quickly. He later ordered another man to kill an entire family inside their home, investigators said.Mexican authorities say Sillas-Rocha participated in the 2010 kidnapping of three women in the family of Ismael "El Mayo" Zambada, who was at the top of the Sinaloa cartel at the time alongside Guzman. Sillas-Rocha allegedly was retaliating for the disappearance of his sister that year.Heaphy said he believes Mexican officials wanted the extradition of Guzman just before Trump took office to be "an Obama victory, not a Trump victory". He said the extradition process will likely become more difficult under Trump, who has riled Mexicans with his pledge to build a border wall and deport people living in the US illegally."I would worry about the potentially acrimonious relationship between our new executive and the Mexican government," Heaphy said. "Extradition is one of the few chips that they have to use in this game of international relations."