I can support your alibi (in a sense...)
The virus in question tries to get itself read by pretending to come from someone else. It picks up addresses from mails in the infected user's inbox and sends out mails in that name using it's own, built in, mail client.
So all you are guilty of is talking too much...
From: "firstname.lastname@example.org" <email@example.com> on behalf of "David Otten" <firstname.lastname@example.org>
Sent: 07 May 2002 03:06
To: "email@example.com" <firstname.lastname@example.org>
I claim that I did not send out the "Lets be |Friends" email that caused
so much pain recently. I left for India on April 23 and did not return
until May 2. My computer was on while I was gone however. I am also pretty
active in keeping my virus software up to date. New releases of McAfee
usually come out on Wednesday afternoon and I pick them up that night.
Finally my computer seemed to be fine when I returned.
This list has certainly come under attack many times in the last year or
two. I hope the recent changes made by Adrian Thomas will help.