public static function delete( $thread_id = 0, $user_id = 0 ) {
		global $wpdb;

		$thread_id = (int) $thread_id;
		$user_id = (int) $user_id;

		if ( empty( $user_id ) ) {
			$user_id = bp_loggedin_user_id();
		}

		/**
		 * Fires before a message thread is marked as deleted.
		 *
		 * @since 2.2.0
		 * @since 2.7.0 The $user_id parameter was added.
		 *
		 * @param int $thread_id ID of the thread being deleted.
		 * @param int $user_id   ID of the user that the thread is being deleted for.
		 */
		do_action( 'bp_messages_thread_before_mark_delete', $thread_id, $user_id );

		$bp = buddypress();

		// Mark messages as deleted
		$wpdb->query( $wpdb->prepare( "UPDATE {$bp->messages->table_name_recipients} SET is_deleted = 1 WHERE thread_id = %d AND user_id = %d", $thread_id, $user_id ) );

		// Get the message ids in order to pass to the action.
		$message_ids = $wpdb->get_col( $wpdb->prepare( "SELECT id FROM {$bp->messages->table_name_messages} WHERE thread_id = %d", $thread_id ) );

		// Check to see if any more recipients remain for this message.
		$recipients = $wpdb->get_results( $wpdb->prepare( "SELECT id FROM {$bp->messages->table_name_recipients} WHERE thread_id = %d AND is_deleted = 0", $thread_id ) );

		// No more recipients so delete all messages associated with the thread.
		if ( empty( $recipients ) ) {

			/**
			 * Fires before an entire message thread is deleted.
			 *
			 * @since 2.2.0
			 *
			 * @param int   $thread_id   ID of the thread being deleted.
			 * @param array $message_ids IDs of messages being deleted.
			 */
			do_action( 'bp_messages_thread_before_delete', $thread_id, $message_ids );

			// Delete all the messages.
			$wpdb->query( $wpdb->prepare( "DELETE FROM {$bp->messages->table_name_messages} WHERE thread_id = %d", $thread_id ) );

			// Do something for each message ID.
			foreach ( $message_ids as $message_id ) {

				// Delete message meta.
				bp_messages_delete_meta( $message_id );

				/**
				 * Fires after a message is deleted. This hook is poorly named.
				 *
				 * @since 1.0.0
				 *
				 * @param int $message_id ID of the message.
				 */
				do_action( 'messages_thread_deleted_thread', $message_id );
			}

			// Delete all the recipients.
			$wpdb->query( $wpdb->prepare( "DELETE FROM {$bp->messages->table_name_recipients} WHERE thread_id = %d", $thread_id ) );
		}

		/**
		 * Fires after a message thread is either marked as deleted or deleted.
		 *
		 * @since 2.2.0
		 * @since 2.7.0 The $user_id parameter was added.
		 *
		 * @param int   $thread_id   ID of the thread being deleted.
		 * @param array $message_ids IDs of messages being deleted.
		 * @param int   $user_id     ID of the user the threads were deleted for.
		 */
		do_action( 'bp_messages_thread_after_delete', $thread_id, $message_ids, $user_id );

		return true;
	}