Zetas boss "El Mamito," captured in 2011

A faction of the Zetas has split off to form a new group called the Legionaries, which is dedicated to waging war on Zetas boss “Z-40,” according to a narco-banner hung in northern Mexico.

The banner in Nuevo Laredo, Tamaulipas, announced the arrival of the group, who call themselves Los Legionarios (the Legionaries). The banners said that the organization was set up to combat Miguel Angel Treviño Morales, alias “Z-40."

Notinfomex blog has the text of the banners, which says:

The Legionaries are a group of renegade Zetas who were betrayed by “Z-40.” [...] 
The Legionaries have the clear mission only to kill people from the Zetas and their families … an eye for an eye.
Our business is solely and exclusively drug trafficking.
We respect the federal forces and their fight to end the narco.

The banners state that the group is led by commanders known as 50, Pegi, and Mamito, who were "betrayed and handed over by Z-40," and that it is present in San Luis Potosi, Zacatecas, Monterrey and Nuevo Laredo.

InSight Crime Analysis

These banners indicate, first of all, that the recent death of Zetas boss Heriberto Lazcano, alias “Z-3,” and capture of Ivan Velazquez Caballero, alias “El Taliban,” has not healed the divide between their followers and those of Z-40. It seems as though Lazcano's and Taliban's fall has caused the divide to deepen, prompting their faction to make a definitive split.

As stated in the banners, the split is thought to have been prompted by accusations that Z-40 had betrayed other members of the group, handing them over to the authorities in order to increase his power. Another theory is that the arrest of Trevino's brother, a racehorse dealer in the United States, caused other members of the group to ask questions about where their profits were going.

At least two of the men referred to as the commanders of the Legionaries are captured Zetas bosses. Jesus Enrique Rejon Aguilar, alias “El Mamito,” was captured in 2011 (see image, above), while “Z-50” is another alias used by El Taliban. It’s not clear who “Pegi” refers to, though Zetas boss Luis Jesus Sarabia Ramon, captured in January, used the alias “Pepito” as well as “Z-44.”

The moralistic rhetoric in the banner, and its declarations of respect for government forces, are far from unusual in Mexico's underworld. Drug gangs often try to distinguish themselves from each other by claiming to be morally superior to their rivals, asserting that they concentrate on shipping drugs rather than extortion or kidnapping, and refraining from killing civilians.

The emergence of the Legionaries is also reminiscent of the birth of the Knights Templar (Caballeros Templarios), who announced their existence on banners in March 2011, after splitting from the Familia Michoacana -- from the crusader-style name of the group to their suggestion of a moral side to their work. Since the split, the Knights Templar have moved to take up much of the criminal territory of the Familia, becoming the dominant group in their homeland state of Michoacan.