CHICAGO — A computer-savvy activist and self-described "communist anarchist" from Chicago was charged Monday with playing a central role in an international computer-hacking ring, allegedly hacking a global intelligence firm and then boasting about making stolen confidential data available online.

Jeremy Hammond, 27, pilfered information of more than 850,000 people via his attack on Texas-based Stratfor and used credit card numbers to make charges of at least $700,000, a 34-page federal complaint says. He allegedly bragged he even snared the personal data of a former U.S. vice president and one-time CIA director.

A lanky, tired-looking Hammond walked into a Chicago courtroom for an initial appearance with his hands shackled, wearing a black T-shirt turned inside out — a six-digit number tattooed on his wrist.

Hammond, who didn't enter a plea, listened as a prosecutor read charges he conspired to commit computer hacking. A judge ordered his transfer to New York, where four others face related charges. Prosecutors linked their activities to a loose confederation of hackers, called Anonymous, and other groups.

When the judge asked if Hammond understood the charges, he responded quietly, "Yes, your honor." As the hearing ended, he could be heard complaining to his attorney that he only just learned of specific accusations — a day after FBI agents arrested him at home Monday night.

Defense attorney Jim Fennerty described Hammond later as someone who has shown compassion for others. Hammond once rallied against plans to hold the 2016 Olympics in Chicago because he felt it would hurt low-income people; another time, he protested against neo-Nazi groups, Fennerty said.

"He's concerned about people and issues — that's why I like him," said Fennerty. He added he didn't know Hammond's personal details, including whether he held a job.

In a 2005 feature article about Hammond's hacking skills, he told the Chicago Reader he could program video games before he was 10. The article mentions accusations — also alluded to in Tuesday's filing — that Hammond had hacked the sites of conservative groups.

He told the paper he was a "hacktivist" who sought to promote causes but never for profit.

He isn't without supporters. A website, freehammond.com, describes Hammond as "one of the few true electronic Robin Hoods."

But Tuesday's complaint, filed in New York, describes Hammond as a dogged, malicious hacker.

In one alleged online chat, Hammond appears to delight in the damage he caused Stratfor. In one message, he allegedly types, "Time to feast upon their (email databases)."

The filing includes odd biographical details, including that Hammond is allegedly a professed "freegan," or someone committed to eating discarded food to counter consumer waste. It says agents saw Hammond going through garbage bins to collect food.

Hammond, who used online aliases such as "crediblethreat" and "yohoho," once described himself as "an anarchist communist," the complaint says.

He had been previously been arrested, including for marijuana possession and involvement in a protest where an Olympic banner was torn down, according to the filing.

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Follow Michael Tarm on Twitter at www.twitter.com/mtarm