In a complaint filed Tuesday with the U.S. District Court for the Eastern District of Virginia, Microsoft identified Andrey Sabelnikov as the suspected botmaster who wrote the code for and either created, or participated in creating, the Kelihos malware, ZDNet.com reported.
The amended complaint comes a few months after Microsoft joined forces with security firm Kaspersky Lab to kill the botnet, which took control of 41,000 computers worldwide and was capable of sending 3.8 billion spam e-mails per day.
In an ironic turn, Microsoft identified Sabelnikov in its complaint as formerly working "as a software engineer and project manager at a company that provided firewall, antivirus and security software."
Microsoft did not identify the antivirus vendor.
The complaint said Sabelnikov is working as a freelance computer consultant and resides in St. Petersburg, Russia.