If it's the latter, however, this is not interesting and there is no reasonable discussion to be had.
Every apprehension under this program is a crime by any definition other than the arbitrary declaration of an illegitimate regime.
It would be absolutely astonishing if the people apprehended were likely to illegally kidnap and hold at least 1 citizen in their basement for at least the length of time that these people are detained.
Thus it can pretty much only increase crime.
It's possible that once enough people who on balance might commit a crime are arrested or impeded, then crime will indeed decrease.
Even if this system works, people who have not committed a crime (yet) are innocent.
Taking an innocent person, and improsoning him against his will is a crime, pretty extreme one.
Even if this system works really well, it's hard to imagine that the crimes it prevents can be more extreme than the crimes it commits.
Every criminal justice system has to balance (1) the risk of convicting the innocent, (2) the risk of letting the true crime-committer commit additional crimes (due to not being caught or caught later), and (3) the risk of being abused. We don’t like pre-crime convictions because we believe risks 1 and 3 outweigh any gains in 2. A culture with a different balance of risks, however, could come to a different but consistent conclusion. I don’t like that conclusion. But it’s at least debatable. Putting political enemies in jail is not.
I don't think so. You could also likely randomly detain people, and the fear you would cause may also reduce crime rates. That doesn't make it right.
This is a loaded research question, of course, because it's studying something that we find abhorrent: Prosecuting people for crimes they haven't actually committed.
Scientifically it's super interesting. Socially and ethically it's a minefield.
This is probably impossible to know, since totalitarian regimes are known for providing completely fake statistics - and it's usually not like they have one set of numbers (real), but publish another (fake), it's that the whole pipeline is hopelessly corrupt so nobody knows the real numbers. USSR was notoriously plagued by this problem - not only for crime, but also for other things like economical statistics.
This system is causing a chilling effect on creativity, differentiation and individualism. It forces people to hide their real thoughts and live a life of constant pretence/lies. It makes the safe-space (the creative-space) to shrink to the interior of one's head. It destroys the ability of population to protest and thus participate in the political life of the country.