The chief executive officer of a major adult beverage company in Japan was compelled to step down from his top-ranked position this week.

Takeshi Niinami, the now-former CEO of beverage maker Suntory, resigned on Tuesday after he found himself subject to a drug-related investigation, according to ABC News.

The company's president and vice president, Nobuhiro Torii and Kenji Yamada, confirmed that they had accepted Niinami's resignation because, regardless of whether he was guilty or innocent of the allegations, he had brought embarrassment to the company.

Resignation announced

Niinmami, 66, became in 2014 the CEO of Suntory, a top producer in Japan of whiskey, beer, and other non-alcoholic beverages, and by all accounts was hugely successful in that position, as President Torii told reporters on Tuesday, "He was a dynamic and decisive leader whom I respect greatly. During a decade of his leadership, both profits and sales grew dynamically."

However, following the news that Niinmami was under investigation for purchasing an unspecified "supplement" that may contain an illegal drug, "governance issues," and the Japanese culture's focus on individual accountability and avoidance of shame, made his resignation inevitable, despite his contributions to the company's success.

Indeed, Vice President Yamada told reporters, "Regardless of whether he is found innocent or guilty, we feel he is not fit for the job."

Under investigation for possessing a cannabis-related supplement

According to CNN, citing unnamed sources, it is believed that law enforcement officials recently searched Niinmami's home for evidence that he'd received from overseas a supplement containing a cannabis-derived substance, which is potentially illegal in Japan.

Products containing THC are strictly regulated in Japan, and possession alone of such products can result in a prison sentence of up to seven years, while charges of distribution or trafficking can bring even more severe punishments.

For Niinami's part, he is said to have assumed that the product he purchased from overseas was legal, but nonetheless submitted his resignation on Monday once it became known that he was under investigation.

Investigation remains ongoing

Yahoo Finance reported that Suntory Holdings, which owns the Jim Beam whiskey brand, among others, said in a statement that Niinmami had shared with the company that the investigation was related to "supplements that were allegedly purchased by him under the understanding that they were legal."

"Given that the matter is under investigation, the company believes that the determination of the legality of the above supplements should be deferred to the authorities," though, in the meantime, it was decided that Niinmami could no longer continue to serve in a leadership position.

"Therefore, without waiting for the outcome of the investigation, the company determined that Takeshi Niinami’s actions, which demonstrated a lack of awareness regarding supplements, rendered him unable to continue in the key position of representative director, chairman, and CEO," the statement added.

No word yet on a replacement or the impact of the resignation

It is unclear what impact Niinmami's resignation will have on the company, as the announcement of his departure came after the Asian markets had closed on Tuesday, during which the company's stock on the Tokyo-based exchange had increased by 2.9%, according to ABC News.

It is also unknown who might take Niinmami's place as CEO, though President Torii indicated that, at least for the time being, he would assume full responsibility for the business, including all of its domestic and foreign operations.