agree. there should be laws that require the fbi to intervene when they encounter a crazy person
I disagree with involving the FBI. Were you just being a smart ass?
In Colorado a family can notify officials that a relative is dangerous and that will trigger a hearing and could result in confiscation of guns and prevent further legal purchases.
The police can also trigger such a hearing if they encounter someone acting dangerously or behaving in a way that would indicate a potential for violence.
Sadly, too many people see these measures as a violation of 2nd amendment rights. In reality these guys are upset because a gun buyer may be inconvenienced...
I've bought a gun from a local shop and sold that gun through that same shop. It was no great problem to obey the law. Background checks were done on both sales.