public function deleteFiles(Model $model, $id, array $filter = array(), $isDelete = false) {
        $columns = $this->_columns[$model->alias];
        $data = $this->_doFind($model, array($model->alias . '.' . $model->primaryKey => $id));

        if (empty($data[$model->alias])) {
            return false;
        }

        // Set data in case $this->data is used in callbacks
        $model->set($data);

        $save = array();

        foreach ($data[$model->alias] as $column => $value) {
            if (empty($columns[$column]) || empty($value)) {
                continue;
            } else if ($filter && !in_array($column, $filter)) {
                continue;
            }

            if ($this->_deleteFile($model, $columns[$column], $value, $column)) {
                $save[$column] = '';

                // Reset meta data also
                foreach ($this->settings[$model->alias][$columns[$column]]['metaColumns'] as $metaKey => $fieldKey) {
                    $save[$fieldKey] = '';
                }
            }
        }

        // Set the fields to empty
        if ($save && !$isDelete) {
            $model->id = $id;
            $model->save($save, array(
                'validate' => false,
                'callbacks' => false,
                'fieldList' => array_keys($save)
            ));
        }

        return true;
    }