Five workers at the Internal Revenue Service (IRS) return processing center in Fresno, California, were charged with computer fraud and unauthorized access to tax return information on Monday for allegedly peeking at taxpayers' files for their own purposes. "The IRS has a method for looking for unauthorized access, and it keeps audit trails, and occasionally it will pump out information about who's done what," says assistant U.S. attorney Mark McKoen. The number of such incidents is apparently on the rise, or the IRS is getting better at sniffing out the perpetrators as there were 430 known cases in 1998, and 521 last year. In these recent charges 13 taxpayers were compromised with each worker allegedly peeking at one to four tax returns, the incidents are from 2005 through 2007. Wired's Threat Level blog suggests "The age of some of the incidents suggests the Inspector General's office is breaking out new algorithms to find anomalies in audit trails going back years."