public static function recheck_comment( $id, $recheck_reason = 'recheck_queue' ) {
    add_comment_meta( $id, 'akismet_rechecking', true );
    
    $api_response = self::check_db_comment( $id, $recheck_reason );

    if ( is_wp_error( $api_response ) ) {
      // Invalid comment ID.
    }
    else if ( 'true' === $api_response ) {
      wp_set_comment_status( $id, 'spam' );
      update_comment_meta( $id, 'akismet_result', 'true' );
      delete_comment_meta( $id, 'akismet_error' );
      delete_comment_meta( $id, 'akismet_delayed_moderation_email' );
      Akismet::update_comment_history( $id, '', 'recheck-spam' );
    }
    elseif ( 'false' === $api_response ) {
      update_comment_meta( $id, 'akismet_result', 'false' );
      delete_comment_meta( $id, 'akismet_error' );
      delete_comment_meta( $id, 'akismet_delayed_moderation_email' );
      Akismet::update_comment_history( $id, '', 'recheck-ham' );
    }
    else {
      // abnormal result: error
      update_comment_meta( $id, 'akismet_result', 'error' );
      Akismet::update_comment_history(
        $id,
        '',
        'recheck-error',
        array( 'response' => substr( $api_response, 0, 50 ) )
      );
    }

    delete_comment_meta( $id, 'akismet_rechecking' );

    return $api_response;
  }