Do you have the moderation log enabled? This will show you moderation actions that moderators (including yourself as an admin) make.
Did you check permissions?
If users got the ability to remove their own posts, well they can and this isn't logged as it isn't a moderator action.
Fixed. You got it right. I didn't think it was anyone else deleting the posts. It was. Thanks for replying.
It's great to have somewhere to post questions and get answers. I've used this forum several times, and now have a better understanding of the my website because of it. Thanks again.