They both carry their own responsibility. I’m sure civil and criminal laws could be applied that are written specifically to cover parental/guardian liability and culpability.
http://www.wnd.com/2018/02/stunning-list-cops-stop-dozens-of-school-attacks-before-they-happen/
The list is incomplete.
Search “kentucky school threat arrests” alone.
Intervention works.
We’re on the same page.
Parents have their bit, but once it reaches law enforcement, they own the reasonable response.
...and where LEOs engage, lives are saved.
Unfortunately, not in this case. LEO, FBI FAILED!