Started by former soldiers and once the enforcement arm of another large cartel, the gang is known in Mexico for its brutality, and its members' calling card is often beheaded victims, body parts on highways and bodies hanged from bridges.
But several analysts said the arrest of Mr. Treviño, led by Mexican marines but supported with intelligence from the United States — where he is wanted on drug and gun charges — could be the beginning of the end of the group as a large cartel and, possibly, the large-scale violence it carried out with such bravado.
Hamby builds part of his case on one word, "corporatism" -- an economic system driven by the planning decisions of large cartels.
The songs also serve as an uncomfortable reminder that Colombia, despite making recent strides against large cartels and drug-trafficking guerrillas, still vies with Peru as the world's largest producer of coca, the plant used to make cocaine.
To some analysts, it is an unintended consequence of the government's strategy in the drug war: as the large cartels splinter, armies of street-level thugs schooled in threats and violence have brought their skills to new enterprises.
And while Colombia has broken up large cartels and seen an increase in drug-related arrests it has not affected the business, said Juan Carlos Garzón, an expert on drugs policy with the Woodrow Wilson Institute in Washington.
The ATF believed that large cartels were smuggling the weapons across the border, but embassy officials viewed that as a myth.
The bloodshed is fueled by the disintegration of large cartels amid heightened competition for control not only of drug trafficking but also of local rackets such as extortion and kidnapping.
The largest cartel fine by the commission, 462 million euros, was served on the Swiss chemicals group Hoffmann-La Roche last year for its role in a cartel in the vitamins market.
Hence, groups of smugglers who used to work on their own or as subcontractors for different bosses were either pushed out of business or forced to join a larger cartel.
The European commission has imposed the largest cartel fine in its history, imposing a €1.47bn (£1.2bn) penalty on seven firms including Philips, Samsung SDI and Panasonic for fixing the price of the now outmoded cathode ray tubes used in televisions and computer monitors.
