After deleted installed extension files order page not working. My order page return Blank page.

Log Error :

exception 'Mage_Core_Exception' with message 'Invalid block type: Mage_Eltrino_Diamantedesk_Block_Adminhtml_Sales_Order_Edit_Tab_Tickets' in /home/giritra/public_html/app/Mage.php:595

Note : Actually i deleted Diamantedesk extension. But still error shown regard Diamantedesk extension.

How can i solve the error?