A social media editor for the Reuters news service was charged Thursday with conspiring with the group Anonymous to hack into the Tribune Co.'s computer system shortly after he was fired from one of the company's TV stations.

Matthew Keys is charged with supplying hackers in December 2010 with the login credentials to the computer network of Tribune Co., which owns the Los Angeles Times, the FBI said. Keys had been fired from a Tribune-owned television station in Sacramento two months earlier during the company's bankruptcy. He was not working for Reuters when he allegedly conspired with Anonymous.

According to the federal grand jury indictment handed down in Sacramento, a hacker altered a Times news story posted Dec. 14 and 15, 2010, to read "Pressure builds in House to elect CHIPPY 1337," a reference to another hacking group.

The indictment alleges that Keys, 26, and another hacker failed in another attempt to access the Tribune computer system after the Times hack. Keys acquired the login information while serving as the web producer for the Sacramento-based FOX station KTXL, which is owned by Tribune Co.

A Tribune spokesman declined comment.

From June 2008 to April 2010, Keys' Facebook page said he worked as an online news producer for the Sacramento station.

"Was a one-man band for two years, updating breaking news, current events, political, entertainment and sports content," read Keys' description of that job on Facebook. "Launched social media platforms to promote content and engage with audience."

Info transmitted in online chat room

Investigators say Keys turned over the information in an online chat room frequented by hackers and members of Anonymous.

Department of Justice prosecutors in court papers allege that a legendary hacker and Anonymous leader named "Sabu," who later turned into an FBI informant, "offered advice on how to conduct the network intrusion." The FBI unmasked Sabu when they arrested Hector Xavier Monsegur on June 7, 2011. Monsegur secretly worked as an FBI informant until federal officials announced he helped them arrest five other alleged hackers on March 6, 2012.

Federal officials declined to comment on whether Sabu assisted in the investigation of Keys.

The day after it was announced that Sabu was an FBI informant, Keys wrote about "infiltrating" the hacker's chat room for Reuters.

The New Jersey native is charged with one count each of conspiracy to transmit information to damage a protected computer, as well transmitting and attempting to transmit that information. If convicted, Keys faces up to 10 years in prison, three years of supervised release and a fine of $250,000 for each count.

Keys is scheduled for arraignment in Sacramento federal court April 14. He didn't respond to email inquiries and messages sent through his Twitter account and Facebook page Thursday.

The indictment comes on the heels of recent hacks into the computer systems of two other U.S. media companies that own The New York Times and The Wall Street Journal. Both newspapers reported in February that their computer systems had been infiltrated by China-based hackers, likely to monitor media coverage the Chinese government deems important.

While Keys did not directly address the federal charges Thursday through his voluminous Twitter feed, even after the news broke he appeared to continue retweeting others' commentary to his more than 23,500 followers, including a story about his indictment.

He did not address the issue on his Facebook page, which shows his last posting Thursday about the best way to make a grilled cheese sandwich.

According to Keys' Facebook page, Keys is single, lives in New York City and currently works at Thomson Reuters' New York office where "I get paid to use Twitter and Facebook at work."

A Reuters spokesman declined comment.