It is difficult to conduct a spy operation in Japanese small islands though the police was in charge of this mission. At first, the operation itself was executed by the police officers, as it was hard to mobilize the local people.
It depends on a size of the island, but it was quite difficult to find collaborators in the smaller islands, even paying for some. At the same time, it was a winter when I went to the Amami islands, hence there were not so many travelers as an off-season.
If they hired a private investigator from the outside of islands, their identity was easily revealed especially when speaking, as their accent was completely different from the local. Their position was more vulnerable than the police, hence they were quite hesitant to take part in an operation in the smaller islands.
This difficulty was the same for the police, as they were not membered by the local people, as all of them hired outside of the islands. It implied the police was generally not trusted that much, or at least, there was no prerequisite the police was always right.
To make this situation more unique, there was no police intelligence officer in the smaller islands. It means the intelligence division at first should have asked a help from the local police station, which was necessary to explain a reason for their operation to win the full trust. After all, the police intelligence sent their officers from the outside as well, whose identity was also easily revealed.
The CIA had more troubles, as they could not run their operation by their own. The information gathering could have been conducted, but they were not able to send many operatives at the same time.
Moreover, any foreigners were quickly spotted as even Japanese travelers could be easily identified. There were almost no local assets living in the island, who could have been sent from the outside, though their identity was also easily revealed that I actually found them out.
The police managed to mobilize the local people under this circumstance, but they just took part in as far as they were comfortable. Therefore, there were many people telling me that there was an intelligence operation going on, which was why I could capture how the spy would conduct a mission more than before.