An American executive at Toyota Motor Corp. suspected of illegally importing a painkiller considered a narcotic in Japan has told police that the tablets in question were not prescribed for her, investigative sources said Thursday.

Julie Hamp, 55, also said that she asked her father to make the shipment of the painkiller oxycodone, which was sent by post to Japan from the United States earlier this month. Japan does not allow the drug, which is used for medical purposes, to be sent through the post.

However, the medicine can be brought into Japan if the bearer also carries a certificate from a doctor.

Tokyo police are considering sending officers to the United States to verify this and other aspects of the investigation.

Julie Hamp, 55, has denied the allegation, telling investigators that the painkiller oxycodone was intended to alleviate knee pain.

On June 18 the Metropolitan Police Department arrested Hamp after 57 oxycodone tablets were found in a package addressed to her. It was mailed from an airport in Kentucky and intercepted at Narita airport.

On Tuesday, police searched Toyota's headquarters in connection with the case.

Sources have said the package's customs label declared that it contained a necklace. Some of the pills were found at the bottom of the package, beneath other items, and some were inside an accessory case.

Hamp, a former General Motors Co. and PepsiCo Inc. executive, was appointed in April as Toyota's chief communications officer, the company's first female managing officer.