MEXICO CITY — The hackers’ message, delivered via YouTube by a man wearing a red tie and a Guy Fawkes mask, was as bold and risky as anything produced by the Zetas, Mexico’s most ruthless crime syndicate. But this time, the Zetas were the target.

They had kidnapped a geek with backup — a respected member of the hackers collective known as Anonymous.

“You have made a great mistake by taking one of us,” said the video’s masked figure. “Release him.”

Or else, the message said, the names of government officials, taxi drivers and journalists who worked with the Zetas would be published online. The goal, they said, was the arrest of these suspected collaborators, but was there a possibility they might be killed by a rival cartel? Yes, said self-identified members of Anonymous, acknowledging the danger. Beyond that, might the hackers also be targeted? Were they afraid?

“Of course,” said a blog post on Monday.

Still, some hackers said, it was time for Netizens to fight back in a country where the news media have been cowed into submission, and where the justice system is often complicit in heinous crimes that regularly go unpunished.