CIA is not the only troublesome agency in Japan, but there is another unforgivable government vehicle, which is Japanese Intelligence.
In Japan, they are one of the divisions at the police department. Generally, they are referred as the Security Police, though its organization is separated into two sub-division, one of which is to conduct the security, including SP and riot squads. The other division is an intelligence service against the terrorist and extremist in Japan.
This Japanese intelligence service is a descendant of the past special police, conducting tortures before World War II, which was abolished when the war ended, but they were come back to deploy against the communist and its extremist, which was one of the big Japanese social movement until 1970s, well known to such as Japan Red Army.
Public Security Intelligence Agency is another domestic vehicle to run an intelligence function in Japan, whose work is totally overlapped with the police intelligence, though they are different in the size. According to WIKI, 1,500 members work as agents in this agency, but 2,000 police officers are deployed to the intelligence service just in Tokyo. That means, it is expectedly 15,000 intelligent officers in total at the police department, whose intelligence size is massive in the global term as well.
The foreign intelligence agencies basically gather the information in Japan, which is why they have Japanese branches, though they plot the conspiracy, sometimes including murders, which is basically the same to Japanese intelligence that they conspire and kill their targets. Having said that, it is quite rare to murder the targets apparently, as it is found easily if obviously executed, hence they kill their targets unnoticeably. That is the reason why it has not emerged as a problem, but there are many assassinations not to be found. Those are executed by foreign agencies in Japan, but at the same time, done by Japanese intelligence as well.
At this point, there is a big problem arisen that Japanese intelligence is one of the vehicles of the police department, so that their wrong conduct is not an issue of legal cases, totally exempted. The misbehavior of each police officer is a matter of the legal action, but the organized crime run by one of the police division is totally free from any issues. The law enforcement and intelligence is conducted by the chief of police organizationally, so that this person has a power to run illegal operations, not bothered by the law.
This chief is picked up by the prime minister, though practically selected by the preceding chief, implying the control is less onto their nomination from the politics in Japan. This is partially because of restricting the corruption between politicians and the police department. If the chief is selected by the politics, the legal decision is more affected by the political reason. In this sense, this Japanese system works to separate those, but there is no way to control the corruption within the police as a result.
Attorney prosecutors are distinctly organized from the police, which has an official power to investigate the corruption case in the police department, though it is less likely occurred, as their litigations are sabotaged by the police department, which makes them deterred to fight against the real issue within the police. In the past, it was just one case investigated by attorneys against the local police. Even in that case, they failed to prove the existence of the organized police crime, while just prosecuting some of the intelligence agents working on that political plot.
The real issue at this structure is that the police exists out of the law. The chief is nominated by the politics, which leaves a room for the slight control, but the chief is basically promoted from the deputy in Japanese tradition, who is assigned by the previous head. It implies the effective control against the police is quite limited, which is applicable to their intelligence conspiracy. However unlawful it is, their action is placed out of the legal control.
The only justification to this structure is that the police is never corrupted so that there is no need to the legal oversight. This is all and the only explanation for this system. However, the police department is so corrupted organizationally in Japan. The politicians are completely under the public watch, though still there are some of them running illegal activity.
On the other hand, the people are obliged to believe the police is always clean, therefore the oversight is unnecessary. The reality is that there is an organized crime within the police department, including unacceptable political conspiracy plotted by their intelligence service and many killings executed by them as well. These are not prosecuted, as they are out of any controls, which is justified by the current police system in japan.
The current system should be revised, but moreover, the intelligence service should be under a control of the politics, to work for the people, not for killing the people. This is necessary to be revised, as the intelligence executes plots commonly in their home country to manipulate the politics to their favors, and they even murder their targets to pursue their own interest anywhere in the world, which is another problem, confronted by the modern world.