Media reports are all we'll ever get. No intelligence agency is going to give us their raw data to examine.
Look, Russia is up to its eyeballs in Iraq. Most of it was perfectly permissible under the UN sanctions, etc. But, it's becoming obvious, even to the disinterested observer, that Russia also had a stake in preserving the Saddam Hussein regime. That's not a crime, but there's no use in denying it, either.