code: public function deleteByQuery($query, array $options = array()) {
          $options += array(
              'refresh' => true
          );
          if (is_array($query)) {
              /**
               * Array implies using the JSON query DSL
               */
              $url = $this->buildUrl(array($this->type, "_query"));
              $result = $this->call($url, "DELETE", $query);
          }
          elseif (is_string($query)) {
              /**
               * String based search means http query string search
               */
              $url = $this->buildUrl(array($this->type, "_query"), array('q' => $query));
              $result = $this->call($url, "DELETE");
          }
          if ($options['refresh']) {
              $this->request('_refresh', "POST");
          }
          return !isset($result['error']);
      }
docs: Search
  
  @return array
  @param mixed $query
  @param array $options Parameters to pass to delete action