(Reuters) -- An alleged member of the LulzSec hacking group who prosecutors say targeted the Fox and PBS television networks and Sony's film and TV studio has been indicted in Los Angeles on federal charges, federal authorities said Wednesday.

Ryan Cleary, 20, who is already jailed in the United Kingdom for prosecution over similar charges, is accused of joining other members of LulzSec in harnessing compromised computers, known as a botnet, to steal confidential information, deface websites or attack servers. He was indicted on Tuesday.

LulzSec, an offshoot of the international hacking group Anonymous, has taken credit for hacking attacks on government and private sector websites, Reuters reports.

Anonymous and its offshoots, including LulzSec and AntiSec, initially focused on fighting attempts at Internet regulation and the blocking of free illegal downloads, but have since taken on other targets including Scientology and the global banking system.

The charges come just over two months after accused LulzSec hacker Cody Kretsinger pleaded guilty in U.S. District Court in Los Angeles in April to taking part in an extensive computer breach of Sony Pictures Entertainment.

In March, court documents revealed that Anonymous leader Sabu, whose real name is Hector Xavier Monsegur, had pleaded guilty to hacking-related charges and provided the FBI with information on fellow hackers.

According to the indictment released by the FBI, Cleary and his unnamed co-conspirators hacked into the computer systems of Fox Entertainment Group and Sony Pictures Entertainment and stole confidential user information. They also attempted to get confidential information on contestants auditioning for The X-Factor, the Los Angeles Times reported. 

The indictment also charges Cleary and his co-conspirators with defacing the PBS website and launching denial of service attacks against an online gaming website and Britain's Serious Organized Crime Agency.

Cleary is charged with one count of conspiracy and two counts of unauthorized impairment of a protected computer. He faces a maximum sentence of 25 years if convicted.

Karen Todner, Cleary's attorney in the UK, didn't respond to an e-mail message seeking comment on the indictment sent after regular business hours, Bloomberg Businessweek reported.

Cleary was charged in England with installing or altering files on Pentagon computers that were controlled by the U.S. Air Force and accessing computers operated by News Corp., its Twentieth Century Fox subsidiary, Sony Corp., the UK's National Health Service, the Arizona State Police, and technology-security company HBGary Inc.

Anonymous, and LulzSec in particular, became notorious in late 2010 when they launched what they called the first cyber war in retaliation for attempts to shut down the WikiLeaks website.

They attacked websites including MasterCard.com, which had tried to block payments to WikiLeaks after apparent pressure from the U.S. government following the release of thousands of diplomatic cables.