Police say they have arrested Julie Hamp, Toyota Motor Corp.'s new head of public relations, on suspicion of importing an illegal pain medicine into Japan.

Hamp, an American, was appointed in April as Toyota's first female senior executive. Police said the painkiller oxycodone, which is illegal in Japan, was found by customs officials in a package she sent to herself by air mail from the United States.

Police said Thursday that the painkiller contained a narcotic, and she was being held in custody. Japanese authorities can detain a suspect without charge for up to 23 days.

They said Hamp denied that she tried to import an illegal drug.

Toyota spokesman Itsuki Kurosu confirmed that Hamp had been arrested.