Toyota Motor Corp. said Wednesday that Julie Hamp, the company’s first female managing officer, has resigned. The American executive stepped down after her arrest last month in Tokyo on suspicion of illegally importing painkiller oxycodone.

Hamp had relocated to Tokyo in June to become Toyota’s chief communications officer, as part of the company’s effort to diversify the male-dominated executive line-up. 

She was arrested on June 18 when local police officials reached at her hotel after they found a drug package mailed to her, Reuters reported. Police officials said, according to local media, that the drugs, which are tightly controlled in the country, were hidden in a package containing jewelry. Five days later, the Japanese police raided Toyota’s headquarters in Tokyo and Nagoya.

Hamp, 55, has not been formally charged in the case, but Japanese authorities are allowed to detain suspects without charge for up to 23 days, the Associated Press (AP) reported. It is not clear when Hamp would be released. 

Toyota said in a statement Wednesday that it accepted Hamp’s resignation “after considering the concerns and inconvenience that recent events have caused our stakeholders.”

“We intend to learn from this incident to help ensure a secure working environment for everyone at Toyota around the world as we continue to take the steps necessary to become a truly global company. We remain firmly committed to putting the right people in the right places, regardless of nationality, gender, age and other factors,” the company said.

While the company declined to disclose more details amid an ongoing investigation, Akio Toyoda, the company’s president, said a day after Hamp's arrest that Toyota should have probably helped her more in her move to Tokyo. He added, according to Bloomberg, that he did not believe Hamp broke the law intentionally.

Foreign nationals have been detained before in the country for mailing or bringing drugs with them, which they use at home, but are banned in Japan or require special approval, the AP reported. 

Hamp joined Toyota in 2012, and had worked with PepsiCo Inc. and General Motors Co. At Toyota, she was supervising marketing and communication for Lexus and Scion brands in the U.S. before she moved to Tokyo.