How El Chapo's Drug Cartel Spread Its Reach Across US

The Sinaloa cartel has grown its reach far beyond the Mexican border and is now believed to be the most powerful and widest-reaching drug importer in the United States.

"They don't necessarily have 80 percent of the market, but they are probably the most widespread and have the largest share out of any [drug trafficking] group in the U.S.," Vanda Felbab-Brown, a senior fellow at the Brookings Institute and expert on Mexican criminal history, told ABC News.

Part of the reason the Sinaloa cartel, which was led by Joaquin "El Chapo" Guzman, who broke out of a maximum security prison in Mexico this weekend for the second time, was able to spread its power so much more effectively than others was because they were "measured" in its use of violence, Felbab-Brown said.

"Sinaloa was very much the instigator of much of the violence in Mexico in the early parts of the 2000s as they were trying to take over the territories of their rivals," Felbab-Brown said, but noted that they were "much more competent in calibrating violence with other policies like social handouts, cultivating the church and they never sort of adopted the same level of violence and carnage" as others.

As a result, the group "never attracted the same level of priority focus from the Mexican government and frankly the U.S. [authorities] as some of the much more brutal groups like the Zetas," she said.

Organizational structure also had a big impact in Sinaloa's footprint, as Felbab-Brown said Guzman "managed to institutionalize power systems and relationships," which allowed the cartel to expand even when he was on the lam before being arrested in 2014.

The Sinaloas also regularly partner with local gangs and drug distributors in the United States to spread their reach. Felbab-Brown described it as franchise-like relationships, with the Sinaloas having a "strong hand."

Twin brothers who coordinated the drug distribution for Guzman in Chicago testified about their operation in November.

Pedro and Margarito Flores testified in U.S. District Court about how they said Guzman would arrange for special 747 planes to fly to Mexico with clothes and supplies for dummy "humanitarian" missions, only to have them cleared out and filled with up to 14 tons of cocaine for the return trip to America, according to The Chicago Tribune.

The brothers, who have been in witness protection for more than five years, said Guzman also regularly used submarines and speedboats to transport cocaine from Colombia to Mexico, The Tribune reported.

Once the drugs arrived in Chicago, they were distributed to cities across the country including Washington, D.C. , and New York, the brothers testified, but government data reports that it was far more widespread.

The Sinaloas specialize in the distribution of cocaine but also are known to work with heroin and methamphetamine, as well, Felbab-Brown said.

In 2009, the now-closed National Drug Intelligence Center, which was run through the Department of Justice, reported that there were 76 U.S. towns that had an affiliation to the cartel. That number marked more than double of any of the six other cartels.

The Drug Enforcement Agency did not immediately return ABC News' requests for comment about the cartel's reach within the United States.

Felbab-Brown does not expect Guzman to fully take over the reins again now that he is out of prison, rather leaving it to the system that he put in place.

"He is not going to go back to being the leader," she said. "He's not going to take over and run every strategic decision... He is going to spend the rest of his life, however short or long that is, in hiding."