Another idea to find the IP's you really want to block would be to go through your website's logs for the day when the person has accessed. If your site is small enough it shouldn't be too hard to find it. You may have to wait until the next time he/she accesses the site and then immediately download the log to narrow it down better. It doesn't work for our site because our logs are over 6MB per day, but it would be very helpful if we were smaller. This would be the IP the server would be looking for to deny or allow access via the .htaccess file.
