A spokeswoman for the National Hi-Tech Crime Unit advised caution, indicating the document could be some sort of vendetta. "It's a little suspicious," the spokeswoman said.
Mikko Hypponen, director of anti-virus research at Sophos who placed a link to the document on his weblog, said the document is credible. "We're duplicating the research to see what we come up with, but the signs are there. Everything they've done seems to make sense. Perhaps initially they wanted a Microsoft bounty."
Microsoft has recently started placing bounties of up to $250,000 on those who create viruses.
In the past such vigilantism has come in for criticism, but Hypponen sees some value in it. "There have been several cases in the past where this sort of thing has been successful. Sometimes law enforcers don't have the time or the perhaps the skills to properly conduct this sort of research." Hypponen said.
Ibragimov has denied any connection with the Sobig virus.