News and logo design

(CNN) -- If you want to scare them away from drugs, this is the cartel you tell your children about.

Los Zetas revolutionized Mexican drug trafficking with their brutality, and that unprecedented level of savagery could mean the end of the cartel's nightmarish reign.

"This is probably the beginning of the end of the Zetas as a coherent, cohesive organization," said Alejandro Hope, a former executive for Mexico's civilian intelligence agency who now serves as security policy director for the Mexico Competitiveness Institute, a Mexico City think tank.

Take the group's leader, Miguel Angel Treviño Morales, aka "El 40" or "Z-40," who was taken into custody this week during a Marine operation south of his hometown of Nuevo Laredo. Treviño had a reputation for punishing his foes with "guisos," Spanish for "cookouts" and the term used for burning someone alive.

With the Zetas, it isn't about murder or torture. It's about making a statement. That statement resounds so effectively that non-Zetas, members of other cartels, dress like the group and claim to be them simply to instill fear.

Mexican drug cartel leader arrested

Police: Hit man admits to 30 killings

See inside a Tijuana drug tunnel

Community police take on Mexican cartels

"Los Zetas is a powerful brand," Hope said. "It is identified with extreme violence. It is identified with a complete absence of scruples."

Though Los Zetas have long been known for their violence, especially after their suspected 2010 massacre of 72 migrants who refused to mule their drugs, two incidents got the attention of U.S. and Mexican authorities, Hope said.

For cartels, business as usual in small-town USA

In February 2011, two U.S. Immigration and Customs Enforcement agents were ambushed in the state of San Luis Potosi. Agent Jaime Zapata was fatally shot. About six months later, several men -- thought to be Los Zetas' extortion enforcers -- torched the Casino Royale in Monterrey, killing 52 people.

"There are many types of drug trafficking," Hope said. "This one is particularly toxic."

George Grayson, a professor of government at the College of William & Mary and co-author of "The Executioner's Men," which focuses on Los Zetas, said in an e-mail that while U.S. and Mexican authorities have zeroed in on Los Zetas, other factors have helped fracture the group. Among them is Los Zetas' massive expenditures on weaponry to defend their turf.

"Over the years, Los Zetas have evolved from a vertical organization with effective command-and-control mechanisms to McDonald's-like franchises," Grayson said, explaining that as Los Zetas' leadership has been eviscerated, the group has relied on groups of "green-as-grass newcomers" who lack the operational savvy of the original Los Zetas.

As have the authorities, the Sinaloa, Gulf and Knights Templar cartels have all turned their attention to taking down the group, and Los Zetas have chosen weak allies in the Beltran-Leyva Organization and Juarez Cartel, Grayson said. The group also lost a key military strategist in Heriberto Lazcano Lazcano, who was killed by Mexican Marines last year, he said.

Former operatives have turned informant, Grayson said, and Lazcano's ally, Ivan "El Taliban" Velazquez Caballero (now imprisoned in Mexico), has accused Trevino of "betraying his comrades in order to get better treatment for his family members captured in the United States."

Hope said many of the top- and second-tier leaders have been killed or arrested, also assisting in Los Zetas' fragmentation.

Los Zetas got their start as enforcers for one of Mexico's oldest drug trafficking groups, the Gulf Cartel, which traces its roots to the 1930s, said University of Texas-El Paso anthropology professor Howard Campbell, who has written extensively on drug trafficking.

The cartel was in disarray until the 1990s, when Osiel Cardenas Guillen, now imprisoned in the United States, "made the Gulf Cartel really super-powerful again, bringing huge loads of cocaine and other drugs into the U.S.," Campbell said.

By the late 1990s, Cardenas found himself at the cartel's helm.

"One of the most innovative tactics he used was co-opting a lot of highly trained military people. He was the first to openly recruit a SWAT-like enforcement wing," Campbell said. "(Cartels) were violent before, but then all of a sudden you have this trained paramilitary wing."

Massacres ensued. Killings were posted on the Internet. Leaving bodies and body parts in public places was a hallmark of Los Zetas' work, as was torture, especially dismemberment. Or as Campbell put it, "chopping up bodies as you would meat in a butcher shop."

Theories abound about what led to the rift between the Gulf Cartel and Los Zetas, but several years ago -- Campbell estimates it was about 2008 -- Los Zetas broke off, "unleashing a tremendous wave of violence all over Northeast Mexico."

Where other cartels, including the rival Sinaloa Cartel, took part in a "patronage network," paying police and government officials for their assistance in illicit enterprise, Los Zetas preferred brutal takedowns of entire towns and regions, Campbell said.

"(Los Zetas) therefore became public enemy No. 1 in Mexico," he said.

They didn't stick solely to drug trafficking, either. Their criminal resume includes extorting business for "protection fees," charging other cartels for passing through their extensive territory, gun and human smuggling, kidnapping and money laundering.

"Violence was a key tool for these guys to obtain all kinds of streams of income," Hope said.

Their turf includes the lucrative drug plaza of Nuevo Laredo and southern Tamaulipas, Piedras Negras, Tuxpan, Coatzacoalcos, La Huasteca San Luis Potosi, Zacatecas and parts of Sinaloa, Tabasco and Nuevo Leon states, Grayson said.

With Treviño's capture, several scenarios could enfold.

His brother could take over, but Campbell, Hope and the geopolitical intelligence firm, Stratfor, all question whether he has the respect or capabilities to head a national criminal outfit.

"I wouldn't bet on that," Hope said.

More violent prospects include the Sinaloa and Gulf cartels attacking Los Zetas in Northern Mexico in a bid to control Nuevo Laredo, "the crown jewel for cross-border flows for goods, services, guns, money, drugs and illegal aliens," Grayson said. Also, the professor postulated the Gulf Cartel could move to take over the Matamoros and Reynosa border crossings.

Another possibility is that the small gangs helping to fill out Los Zetas' ranks could begin operating independently or be absorbed by other cartels, several experts said. This would be similar to what happened after Colombia broke up the Medellin and Cali cartels.

" 'Cartelitos' emerged that were violent and successful in shipping cocaine, but did not pose a threat to the nation-state," Grayson said.

Whatever happens, don't expect much impact on the U.S. side of the border, said author Charles Bowden, whose books on the Mexican drug war include "Murder City: Ciudad Juarez and the Global Economy's New Killing Fields."

"His arrest means nothing," Bowden said. "None of the arrests under (former President Felipe) Calderon affected the shipment of drugs to the U.S. or the price of drugs in the U.S."

Added Hope, "To affect the volume of drugs going into the U.S., there needs to be a reduction in the demand for drugs in the U.S."