As mentioned, there was one police officer, also a believer of the Aum cult, confessed he might have shot the director general, though this phenomenon was exactly a result of the twilight learning, one of the established methodology of the brainwash until then.
The voice had been delivered directly to the brain by the electromagnetic wave until the 1980s. At least, I witnessed in in 1993, which was before this shooting in 1995.
The twilight learning was a methodology to create a new memory against the subject. There is a window time directly access to the long-term memory during the REM sleep and you create a false memory if talked to under this state.
This created memory basically has a flaw of the causality, hence you can identify it if you know you are a subject of this brainwash. However, you recognize it as a true memory more easily if you have no idea of this skillset. This brainwash works more effectively if continued every day.
This brainwash was established in the 1970s and the CIA and other intelligence fully realized it, though it was not one of the electromagnetic wave technology at the beginning. It started from the experiment to talk to the subject physically during the REM sleep. Having said that, the REM sleep was confirmed by the EEG, i.e. the same technological background, easily advanced to the electromagnetic wave manipulation.
One of the journalists, Yo Tanigawa, claimed that the memory of this shooter was eliminated, which was one of the main possibilities considered in the past. The Aum cult invented a methodology called as “narco” to eliminate a memory of the subject. You can find a doctor who invented this technology behind the bar, but I assume he wiped out the memory cell itself.
The electromagnetic wave can wipe out the memory as well, which I have experienced numerous times, but it did not eliminate the brain cell. The synaptic connection is basically failed due to the electromagnetic wave and the memory is lost for the time being, but it can be reconnected as each memory cell itself is not damaged by this operation.
After all, the memory can be wiped out just to affect the synaptic connection.
On the other hand, I assumed the Aum used much higher frequency to wipe out the memory. The electromagnetic manipulation basically avails an ultra-long wave for the synchronization of the brainwave to the outside electromagnetic wave. The Aum was likely to give a pulse to the certain brain address to collapse the memory cells itself.
I could not confirm whether I correctly captured their methodology, but the point is that this police officer was not wiped out his memory, but the new memory was added to his brain. This was not a result of the Aum technology, as they were just able to wipe out the memory, not creating a new one.
The twilight learning through the electromagnetic wave is the only way to manipulate the subject covertly, even though there are other possibilities if manipulated opaquely.
This police officer lived under the police intelligence control after his confession, which was a team to have a skillset of this electromagnetic wave. His confession was obscure in the detail, which was not a result of the memory loss, but his memory was created with a flaw of the causality.
This operation was conducted to hide the true nature of this shooting.