There were several ways to obtain the personal information in those days, through this PI’s network. When a private investigator was asked to find an address from the car number plate, this guy contacted another who had an access to this information.
This information was administered by the police department, hence it was easily obtained when paying some for it to a police officer of an internal collaborator. There were several people arrested for this misconduct, which was a story in 2012, almost the same period.
One of this information was originally sought by yakuza who would like to blackmail another police officer for his standing on the court against. It meant the police internal information was passed through the PI’s network to sabotage the police activity.
There was another prominent way to get the personal data from the mobile phone shop. When the PI’s network cracked one of the shop managers, they could trace back an address from its phone number easily.
These methodologies were illegal and are still unaccepted, but I am not sure these flaws were buried permanently or not. These issues were revealed around 2012, which showed that the police was highly involved with this PI’s network. The criminal case was charged that the network availed the police officers, but actually, the police department also leveraged it for their covert operation.
However, the police was not able leave the network as it was, because it became more apparent availed by criminals. They called this network as a crime infrastructure and declared to demolish it, but still intact. This was obviously used for the famous fraud case in Japan, still costing several hundred millions of dollars per year, though not demolished.
I truly believe they have had no intention to break this down, as this PI’s network is used by the police for their illegal covert operation. If they threatened PIs for an arrest, they can mobilize them at a cheaper cost, which is better than to eliminate a dangerous network.
Although, I have no confirmation at this point. There should be some reasons why they are still around me to conduct a gaslighting and harassment. It is highly likely motivated by money, which is provided by the police intelligence and CIA, though it is impossible for me to get its proof.