Did you check your Admincp > Statistics & Logs > Control Panel Log to see if it is shown there? Did you check your access_logs (if you don't know where they are, ask your host) for that day to see who entered the admincp and modcp that day and verify those IPs are your actual admins/mods? Did you check your server access logs to see if anybody but you has logged into the server (and thus had access to the database)?