AjiNIMC - 10:57 am on Mar 3, 2009 (gmt 0)
The email states (in different words) it looks like a 3rd party has modified your pages, so they seem to know it's not the site owner to blame, further down it also says google would like to keep his site in the index.
Last week when we were at Google, Adam spoke about this in detail. He explained how applications like wordpress get hacked now and then. They see this more often that we think. May be this frequent hacks have forced them to believe (and program) that it is a 3rd party.