Microsoft claims that it did ask Google to join the Nortel patent bid along with Apple and Oracle, but Google declined.
Frank Shaw, Microsoft's corporate communications head, took to Twitter to post a screenshot of an email from Kent Walker, Google's general counsel, in which the company decides not to join the patent coalition.
The email, sent in October 2010, reads, "After talking with people here, it sounds as though for various reasons a joint bid wouldn't be advisable for us on this one."
The snarky tweet from Microsoft comes in response to Google's spiky blog post that accuses the tech giants of carrying out a "hostile, organised campaign against Android" by buying up the patents.
Microsoft, Apple and Oracle in a group known as CPTN bought the patents for $3.5 billion more than the predicted price.
Google hinted in its blog post that "these deals are likely to draw regulatory scrutiny", which suggests that it has its legal teams raring to fight any patent claims tooth and nail.
While one email doesn't give us a clear picture of the situation, it certainly achieves Microsoft's aim of making Google look a bit silly.
Who can really be the winner in this great patent war? Not, we suspect, the buyers of phones.