Grupo Zeta

As to what I've heard, aren't they like the robin hoods of Mexico? If heard that they threaten merchants of unfair pay to their employees, etc.

Los Zetas is a paramilitary criminal gang that operates as a hired army for the Mexican Gulf Cartel. Los Zetas have set up camps in which to train recruits as well as ex-federal, state, and local police officers. The group is extremely well armed, they wear body armor and some wear Kevlar ballistic helmets; their arsenal includes AR-15 and AK-47 assault rifles, MP5 submachine guns, 50 cal. machine guns, grenade launchers, ground-to-air missiles, dynamite and helicopters. They are known to operate with modern wiretapping equipment and purchase the cellular phone codes of their intended targets directly from the phone companies and providers. Los Zetas are known to operate with a higher tactical degree than the local authorities. During one shootout against law enforcement the group employed grenade launchers and 50 cal. machine guns. The group has been linked to monitoring and kidnapping of journalists, and the murder of rival cartel members and their families. Los Zetas have been known to hire local gangs such as Texas Syndicate, MS-13 and Hermanos Pistoleros Latinos to carry out contract killings. Often, Los Zetas operate while uniformed as Federal Preventive Police and driving similarly labeled vehicles. Los Zetas are involved in myriad criminal activities. They have branched out into kidnappings, murder-for-hire, extortion, money-laundering and human smuggling. For security purposes, Los Zetas have adopted a cell-like structure to limit the information that any one member of the organization knows about his associates. The were involved in the shootout that left two Acuna police officers dead that occurred about two years ago. Lately they have been going into the Acuna night clubs and restaurants with their assault rifles and searching everyone in the building and not allowing anyone to leave, until they are done with whatever objective they have. My only concern is that the local media has done nothing to address this situation, for lack of knowledge or maybe for fear of retaliation. I feel it is important to let the community know that if they go across into Acuna, they are going at their own risk.

I'm ignorant on this one, could you please tell who or what "Grupo Zeta" is and why has it or they made travel to Acuna dangerous?