"Double investigation system in one case" means that public security organs need to conduct criminal investigation and administrative investigation at the same time in the clue verification of cases involving black and evil. Specifically, after the public security organs find clues related to black and evil, in addition to immediately starting criminal cases related to black and evil, they also need to simultaneously carry out administrative investigations, comprehensively investigate and recover the economic activities and assets of the people involved.

The "double investigation system in one case" is mainly to comprehensively manage the criminal activities involving black and evil, not only to dig deep into the interest chain, organizational structure and industry penetration behind the crime, but also to impose economic punishment and asset investigation on criminals to prevent them from resuming criminal activities through illegal channels.

At the same time, the "double investigation system in one case" can also strengthen the legal sanctions against triad-related and evil-related cases, effectively deter triad-related and evil-related crimes and maintain social security and stability through judicial decisions, administrative penalties, and recovery of illegal income of those involved.

It should be noted that the "double investigation system in one case" is not implemented for all criminal cases, but a measure for comprehensive management of cases involving black and evil. For other types of criminal cases, the public security organs will investigate and deal with them according to the specific circumstances and legal provisions.

I hope my answer is helpful to you.