"Certainly, companies need to be extra vigilant," he said. "We continue to encourage companies to be extra cautious and monitor carefully their procedures regarding laid-off employees. And they need to call the authorities at the first threat."

Late on the morning of Thursday, Nov. 6, Savtyrev used a Gmail account to e-mail the company's general counsel and three other employees, saying he was "not satisfied with the terms" of his severance, FBI Special Agent Gerald Cotellesse wrote in the complaint. The FBI charged that Savtyrev threatened to cause extensive damage to the company's computer servers if it didn't increase his severance pay, extend his medical coverage and provide "excellent" job references.

The sysadmin also threatened to alert the media after attacking the server.

According to the complaint, the company contacted law enforcement personnel the day of Savtyrev's first threat. That evening, at the direction of investigators, a company employee recorded a phone call in which Savtyrev repeated his demands. During the call, he also said he would get his "comrades from Belarus" to help him hack into the company's servers, the complaint said.

Savtyrev sent a second e-mail to the company on Friday, Nov. 7, and in a taped phone conversation that evening agreed to show company officials how he could exploit the systems in return for meeting his demands, the complaint said.