In 2014 three guys in my building in Isla Vista were was stabbed to death by their roommate. That killer would, in virtually any other developed country, have been remanded into mental heath care facility for mandatory treatment of BEFORE those murders. We also know that the mass murderer in Parkland would have been remanded before committing his mass murder in most other countries.
When I had read in the local press that the isla Vista murderer 's parents had desperately been trying to get him committed before those murders, I found out why they could not: Decades of relentless and irresponsible efforts by the ACLU (American Civil Liberties Union) to make it almost impossible to get someone remanded in the US . If you go to the US NIH site, which has a good search function for academic articles on medical issues, there are actually peer reviewed studies documenting how a huge number of dangerous conditions combined with demonstrated dangerous behavior, allow the authorities in Australia, Canada, the UK, Japan, France, Sweden, Denmark etc to bring a person in for evaluation easier and have lower probative thresholds for commitment and compulsory treatment.
Louis doesn't go into ANY of that in this series. The issue of mental health is not just about after a crime, but about prevention. The ACLU has made it virtually impossible to prevent some of these crimes.