A computer programmer linked to the online hacktivist group Anonymous who pleaded guilty to hacking the intelligence firm Stratfor was sentenced Friday to 10 years in prison, prosecutors said.
Jeremy Hammond, 28, whose case has been supported by digital rights activists and others, also was part of a group which broke into the FBI computer network and later delivered documents to WikiLeaks, according to investigators.
He was sentenced by a US federal judge in New York after pleading guilty in May to conspiracy charges in connection with the 2011 hack of Stratfor.
"As he admitted through his plea of guilty, Jeremy Hammond launched a series of computer hacks that stole confidential information pertaining to companies, law enforcement agencies, and thousands of innocent individuals," US Attorney Preet Bharara said in a statement.
"His sentence underscores that computer hacking is a serious offense with damaging consequences for victims, and this office is committed to punishing the perpetrators of such crimes."
Officials said Hammond and his co-conspirators stole Stratfor emails as well as account information for approximately 860,000 Stratfor subscribers.
Officials also say the group stole credit card information from 60,000 credit card users and used that to make more than $700,000 in unauthorized charges.
His supporters claim he was exposing wrongdoing, some comparing him to Chelsea Manning, the US army private prosecuted for giving some 700,000 classified diplomatic and military documents to WikiLeaks.
The "Free Jeremy" website claims Hammond was prosecuted for "leaking information... which revealed that Stratfor had been spying on human rights activists at the behest of corporations and the US government."
The Electronic Frontier Foundation argued in a brief that Hammond "did not profit financially as a result of his actions, but rather, exposed uncomfortable truths."
Hammond read a statement in court claiming his acts were "civil disobedience."
"The acts of civil disobedience and direct action that I am being sentenced for today are in line with the principles of community and equality that have guided my life," the statement text said.
"I hacked into dozens of high profile corporations and government institutions, understanding very clearly that what I was doing was against the law... But I felt that I had an obligation to use my skills to expose and confront injustice -- and to bring the truth to light."
Hammond also highlighted the role of a government informant, Hector Monsegur, known by his nickname Sabu, in the case.
"I had never even heard of Stratfor until Sabu brought it to my attention," he said.
"Sabu was encouraging people to invade systems, and helping to strategize and facilitate attacks. He even provided me with vulnerabilities of targets passed on by other hackers, so it came as a great surprise when I learned that Sabu had been working with the FBI the entire time."
The intrusions "were suggested by Sabu while cooperating with the FBI," and foreign government websites as well, according to Hammond's statement.
Hammond was among five people indicted in 2012 alleged to be members of Anonymous, Lulz Security and other international hacking groups.
The indictments cover some of the most notorious hacking incidents of the past several years including those against Sony Pictures Entertainment, Stratfor and computer security firm HBGary.
Hammond, who could have faced a longer prison sentence before his "non-cooperating plea agreement," admitted his involvement in computer intrusions into the FBI Virtual Academy, the Arizona Department of Public Safety and other government networks.
The Hammond case is linked to that of Barrett Brown, a journalist and former spokesman for Anonymous who faces up to 105 years in prison.
The Brown case is being watched by media rights activists who argue that he was targeted for sharing links of Hammond's hacked materials. But he also faces charges of threatening a federal agent. His trial is due next year in a Texas federal court.