Entourage Mailbox Emails "Lost"

I am looking for emails that I can find using Spotlight but that don't show in Entourage. I imported mail into Entourage, then moved all the emails from one mailbox into Out (by accident). They disappeared from Entourage. BUT when I search for one using Spotlight, it is listed and I can open it. Is there a way to retrieve these emails? (By the way, there are several thousand of them.)

Failing that, I will re-import the messages. Then how do I delete the old emails so they don't show whenever I do a spotlight search.

Thanks.