Index: src/bp-messages/classes/class-bp_messages-thread.php
===================================================================
--- src/bp-messages/classes/class-bp_messages-thread.php	(revision 9742)
+++ src/bp-messages/classes/class-bp_messages-thread.php	(working copy)
@@ -309,8 +309,20 @@
 
 			// Delete all the recipients
 			$wpdb->query( $wpdb->prepare( "DELETE FROM {$bp->messages->table_name_recipients} WHERE thread_id = %d", $thread_id ) );
-		}
+		} else {
+            /**
+             * Fires after a message is marked deleted. This hook is poorly named.
+             *
+             * @since BuddyPress (1.0.0)
+             *
+             * @param int $message_id ID of the message
+             */
+            foreach ( $message_ids as $message_id ) {
 
+                do_action( 'messages_thread_deleted_thread', $message_id );
+            }
+        }
+
 		/**
 		 * Fires after a message thread is either marked as deleted or deleted
 		 *