The police questioned several people including employees and a former executive of a Toyo Tire & Rubber Co. subsidiary in connection with the shipment of products using substandard earthquake shock absorber material, investigative sources said Friday.

Osaka police are investigating the case as possible label falsification as they suspect that the Osaka-based Toyo Tire and subsidiary Toyo Chemical Industrial Products Co. intentionally modified data related to the quality of products before shipping, a possible violation of the unfair competition prevention law.

The police are expected to consider whether to bring charges against those involved after examining whether others including then Toyo Tire & Rubber executives, who are believed to have been told of the falsification, were in fact aware of it, the sources said.