Mail Question

Mail Question: Previous Recipients: I am having a strange problem with my Mail previous recipients list. I've delete MailRecents-v4.abcdmr from the appropriate place in the Library and have logged out and then logged back in on my account. When I select Previous Recipients from the Window menu, the list is empty, but when I type a known contack address into the To: line on an email, I still get a long list of possible addresses that are not in my Contacts. These same addresses could not be found in my listing of previous recipients before I deleted MailRecents-v4.abcdmr. Does anyone have an idea where these unknown addresses might be coming from and how to get rid of them?