The Metropolitan Police Department arrested Julie Hamp, Toyota Motor Corp.’s first female managing officer, on June 18 on suspicion of importing oxycodone, an opioid used to relieve pain. The drug is tightly controlled in Japan but can be imported into the country with a prescription if certain procedures are followed.

Hamp has since tendered her resignation via a lawyer, according to a statement posted on Toyota’s website on Wednesday. She hasn’t been able to speak with the company directly because she has been in detention since her arrest.

According to weekly magazine Shukan Shincho, Hamp is being held in a detention cell at a police station not far from the United Nations University in Tokyo’s Shibuya Ward. She hasn’t been formally charged yet and the odds are very high that she will be held for the entire 23 days allowed under Japanese law.

Hamp told prosecutors she had the powerful painkiller shipped from the U.S. to ease problems with her knees, The Japan Times reported Wednesday, noting that her father is believed to have mailed the package to her.

Hamp claims she was unaware she was breaking the law.

It doesn’t matter — once prosecutors have filed formal charges, a guilty verdict is almost certain. The country has a conviction rate that exceeds 99 percent, which has been attributed to prosecutors presenting judges with only the most obviously guilty cases.

Those in detention are routinely treated as if they are guilty and if suspects don’t know how the system works on their first day inside, they soon learn quickly from other inmates. Suspects who protest their innocence are treated badly. Suspects who don’t confess to committing a crime are unlikely to be granted bail at all. If prosecutors decide to file formal charges, a suspect could be held in detention until their trial — which could be months away.

What is life like in the police detention cells? Suspects are put in a cell with several other inmates. They’re not allowed to call each other by name, only by a number. Inmates wake up at 6 a.m.; they go to bed at 9 p.m. The food is always served cold, except on rare occasions. Suspects aren’t allowed access to a phone, iPod or computer. They generally aren’t allowed reading materials unless they are in Japanese.

Suspects are allowed one 20-minute visit per day, excluding their lawyer. They have the right to remain silent but don’t have the right to have an attorney present. The lights in the cells are kept on all night. Inmates are not allowed to cover their heads. The police can interrogate suspects for as long as they like, although they generally restrict this to no more than eight hours a day.

The monotony, poor treatment, isolation and despair that suspects experience in detention are enough to make many jump at any chance to be released before their trial. It has resulted in “confessions” that have later proven false.

Hamp is likely to still be in detention at the time this article is published.

At first, Toyota was very supportive of her. President Akio Toyoda apologized for the incident at a news conference, saying he believed Hamp had no intention of breaking the law.

“To me, executives and staff are like my children,” he said. “It’s the responsibility of a parent to protect their children.”

His unabashed support for his ‘child’ did not sit well with the police, who probably felt as if they had lost face. They raided Toyota’s offices on June 23.

The police have judiciously leaked information to bolster their case since the arrest and the country’s newspapers have had no hesitation in reporting it under headlines such as “Medical exam shows no need for painkiller,” “Police fearlessly take on Goliath company” and the vaguely xenophobic “Diversification a problem for Japan.”

In the end, Toyota accepted her resignation on July 1, because of “the concerns and inconvenience that recent events have caused our stakeholders.”

Does anyone really believe that a high-paid executive of Toyota was smuggling oxycodone into Japan in an attempt to get high or, worse, sell it to a third party?

However, the police and the prosecutors aren’t bad people — they’re just doing their job.

In 2002, Briton Nicholas Baker was accused of smuggling drugs but he claimed he was set up by another man, James Prunier.

The police in Belgium, who were pursuing Prunier, wanted to provide evidence to courts in Japan that might have exonerated Baker. However, the prosecutors refused to accept the evidence.

After persistent nagging, a representative from the Chiba Prosecutor’s Office met with me. I asked him why the prosecution refused to talk to the Belgian police. He looked at me, dumbfounded.

“We have everything we need to win this case,” he said. “Why would we want evidence that weakens it?”

Prosecutors don’t seem to care so much about justice — it all comes down to winning the case. Hamp may simply be on the losing side; her guilt or innocence is irrelevant.

That said, the arrest took place after a meeting of Toyota stockholders, suggesting that the police showed some concern for the corporation.

National Police Agency sources say Eriko Yamatani, chairman of the Public Safety Commission, which oversees the country’s police force, was consulted as well before the arrest. This in of itself isn’t odd — Toyota is a major pillar of the domestic economy.

It’s worth noting, however, that weekly magazine Shukan Bunshun has previously accused Yamatani of being associated with Zaitokukai, an ultranationalist group that has been condemned by the United Nations, the United States and the National Police Agency.

In the end, Hamp will probably confess — almost everyone does. Unfortunately, however, her “confession” may only serve to reinforce Zaitokukai’s view that non-Japanese are nothing but trouble.

There’s another word for a presumption of guilt or preconceived opinion that is not reasonable: prejudice.

Dark Side of the Rising Sun is a monthly column that takes a behind-the-scenes look at news in Japan.