By Stewart Tongue

YNOT – A fourth member of the hacker collective known as LulzSec has been arrested in Tempe, Ariz. He and another Tempe man who was arrested last year are charged with conspiracy and unauthorized impairment of protected computers for their alleged roles in high-profile attacks on British government offices, PBS, Sony Pictures Entertainment, Nintendo, the CIA and the U.S. Senate.

Raynaldo Rivera, 20, faces up to 20 years in prison if convicted. He is set to face a judge in Los Angeles Sept. 14.

In June 2011, LulzSec claimed credit for hacking more than 50 adult websites and posting usernames, passwords and email addresses online. According to the group’s website (since removed from the web) and Twitter stream (inactive since July 27, 2011), the hackers wanted to call attention to the large number of .mil and .gov email addresses on the membership rosters at the porn sites.

Two weeks after breaking into the adult websites, LulzSec announced it would go forth and hack no more, possibly as a result of the arrest days earlier of an alleged group member in London. Ryan Cleary, 19, was nabbed on suspicion of violating the Computer Misuse Act and the Fraud Act after authorities traced an incriminating IRC server to him. Shortly before Cleary’s arrest, the group had bragged its members were untraceable.

Cody Kretsinger, 24, also of Tempe, was arrested last year. In April 2012, he pleaded guilty to hacking-related charges and faces sentencing Oct. 25.

In late August, LulzSec’s alleged leader, 28-year-old Hector Monsegur of New York, pleaded guilty to several federal hacking crimes. After his arrest last year, he reportedly assisted the FBI in identifying and tracking down six other LulzSec and Antisec members while continuing to direct his group for about six months. Monsegur faces up to 124 years in prison when he is sentenced in February 2013, although his sentence may be reduced because he cooperated with authorities.

Both LulzSec and Antisec are thought to be offshoots of the massive international hacking group Anonymous.