[CentOS] RSync Problem

I use an external USB drive and rsync to back up everything in /home. The USB drive has an entry in fstab and I mount it with "# mount /mnt" The rsync command I use is:

rsync -av --delete --include='.thunderbird' --include='.filezilla' --include='.putty' \ --exclude='.*' --exclude='Desktop' --exclude='VirtualBox*' /home/* /mnt/home/

After I deleted one of the users on my system, including their home directory, I ran the rsync command. I found that the deleted user's home directory wasn't deleted from /mnt/home. I thought that the --delete option deleted everything on the destination that was not on the source.

Please help. Thank you, Joe