A fired Massachusetts state worker has been exonerated of a charge of possessing child pornography after computer forensics showed that his work laptop was infected with malicious software that was surreptitiously visiting illegal Web sites.

Michael Fiola, 53, was fired as a worker's comp fraud investigator with the Massachusetts Department of Industrial Accidents in March 2007 after IT administrators found cached images of child porn in the temporary Internet files in his browser, according to the Dark Reading security news site.

Fiola, described as being "computer illiterate," hired a forensics expert who found the evidence that was used to convince the court to drop the case last week. He remains unemployed and plans to sue the agency over his firing.

"Our lives have been hell," Fiola, a former state park ranger now living in Rhode Island told the Boston Herald. "I hope to recover my reputation, but our friends all ran."

His laptop initially attracted attention because its wireless usage was four times higher than that of his co-workers. But because the IT department hadn't properly configured the agency laptop and antivirus software wasn't working on the machine, it was riddled with Trojans and viruses, in addition to the malicious software that was bringing up the porn sites.