(CNN) -- A video purporting to be from a vigilante group whose goal is the eradication of the Zetas cartel from the state of Veracruz, Mexico, has surfaced on the Internet, but its credibility remains unproven. Five masked men dressed in black appear on the video, sitting behind a long table. The spokesman explains that they are a group called the "Mata Zetas," or Zeta Killers. They describe themselves as an "extermination" force that works as the armed front "of the people and for the people." The speaker says that the group's only goal is to kill members of the Zetas, a ruthless cartel whose area of influence includes the eastern state of Veracruz. Members of the Mata Zetas are prohibited from committing crimes such as extortion or kidnappings, according to the video.
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A group called "Zeta Killers" releases a video on the Internet
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The group says its goal is to exterminate the Zetas cartel from Veracruz state
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Authorities say that they will investigate any group that takes justice into their own hands
The group left notes next to bodies, claiming that the victims were @placeholder or supporters of the Zetas.