A 39-year-old employee of Japanese e-commerce giant Rakuten Inc. has been arrested on charges of attempting to smuggle a stimulant drug from Taiwan into Japan, police said Tuesday.

After arriving at Tokyo’s Haneda airport from Taiwan on Sunday, Kunio Hatanaka was arrested when customs officials found the stimulant drug in his belongings.

He is suspected of possessing about 118 grams of the drug, hiding it in a backpack and the bottom hem of his trousers.

A search of his home in Tama, Tokyo, on Tuesday morning uncovered 1.2 grams of a crystallized stimulant drug in a bag, about 20 glass pipes and more than 100 assorted small bags.

Hatanaka, who has denied the allegations, had visited Taiwan 143 times since January 2008, the Metropolitan Police Department said. He is also suspected of using the drug after testing positive in a urine test after his arrest.

He was quoted as telling the police, “I didn’t bring it on my own will. I don’t know when or how the stimulant drug got there.”

A man who was convicted of possessing a stimulant drug in a trial last May told investigators he “bought it from Hatanaka.”

A Rakuten official said, “It is extremely regrettable if (the allegation) is true, and we will consider dealing with the matter strictly.”