TOKYO, Japan — The German CEO of major Japanese optical equipment maker Olympus has resigned after allegedly purchasing illegal drugs, the company announced Monday.

Stefan Kaufmann became CEO in April 2023, having been a member of the board of directors since 2019. He first joined the European branch of Olympus in 2003.

Olympus shares plunged six percent in morning trading as the company apologized in a statement “for the concern this has caused our shareholders, customers and all stakeholders.”

“After receiving an allegation that Mr. Stefan Kaufmann had purchased illegal drugs, Olympus, in consultation with external legal counsel, immediately investigated the facts, made a report to the investigating authorities and cooperated fully to their investigation,” the statement said.

The company’s board subsequently “unanimously determined” that Kaufmann “likely engaged in behaviors inconsistent with our global code of conduct.”

Kaufmann, who would be the company’s second non-Japanese president, was asked to tender his resignation, which the board later accepted, Olympus added.

Olympus announced in 2020 that it was selling its struggling camera division to focus on medical equipment. The company had been in the camera business since 1936, but struggled with industry competitors after the advent of smartphones.

The famous company has achieved success in the field of medical equipment and controls a large part of the global endoscope market.

Olympus Chairman Yasuo Takeuchi will serve as CEO “for the time being” while the board’s nominating committee considers “all options for a successor,” the company said.