Updated

An Internet video is threatening Mexico's Zetas drug cartel with exposure of its allies in the local police and news media this week unless the gang frees a kidnapped member of the international hacker movement known as "Anonymous."

The YouTube message, which claims to be from Anonymous "Veracruz, Mexico and the world," says it is "tired of the criminal group the Zetas, which is dedicated to kidnapping, stealing and extortion," and threatens to fight back with information instead of weapons.

It said it knows of police officers, journalists, taxi drivers and others working with the Zetas.

The video refers to an unidentified person kidnapped in the coastal city of Veracruz, and says: "You have made a great mistake by taking one of us. Free him."

The hacker group, which has claimed responsibility for attacks on corporate and government websites worldwide, supposedly will act Friday if the kidnapped activist is not freed or is harmed, according to the message.

"We cannot defend ourselves with weapons, but we can with their cars, houses, bars," the message adds, apparently alluding to properties owned by cartel supporters. "It's not difficult.

We know who they are and where they are are."

"Information is free," it says. "We do not forgive. We do not forget."

An official with the Veracruz state attorney general's office, who could not be named because he was not authorized to speak on the record, said the office could not confirm video's authenticity or the case of the kidnapping.

Veracruz, an oil state on the Gulf of Mexico with a major port of the same name, has seen a spike in drug violence in recent months in what authorities say is a battle between the Zetas drug cartel, which has controlled the territory for at least a year, and its rivals. Dozens of bodies have been showing up in recent weeks, including the dumping of 35 last month on a main highway in rush-hour traffic in the city of Boca del Rio.

Two other Internet postings since July have announced the arrival of group that calls itself the "Mata Zetas," or Zeta Killers, who authorities say are likely aligned with the powerful Sinaloa Cartel. Others have raised questions about whether the group's members are vigilantes or other rogue bands taking justice into their own hands against the Zetas.

The new message, presented by someone wearing a theater mask that is a trademark of Anonymous, was reportedly uploaded to websites early this month, but was first reported Friday on the website of the global intelligence think tank Stratfor.

Stratfor, in its analysis of the video, said anyone exposed by Anonymous as a Zetas collaborator -- accurately or not -- would be targeted by rival gangs, and the Zetas could respond by attacking Internet activists even if they are not affiliated with Anonymous.

Three people have been killed recently in the northern states of Nuevo Leon and Tamaulipas by suspected Zetas who apparently believed the victims used the Internet to spread information about the gang.