More info in the investigation.
The first time the Cops had contact with the shooter was when it was reported he'd told people he was going to commit suicide.
The second interaction was when he threatened to kill his family. Cops confiscated 16 knives, a dagger and a sword, which were all returned after the father claimed they belonged to him. The father also promised to have the son see a mental health professional.
The shooter was never charged with any crime even with the previous behaviors. When he wanted to buy guns, the father sponsored him to get a Firearm Owner ID, required by the state to buy a gun. Since he was under 21, the law required an adult sponsor him to have his FOID approved.
So, to me, this boils down to what's really a problem with red flag laws. The lawmakers (and the red flag proponents) believe the family is in the best position to observe and report the behavior of their family members. The problem is, most family members are hardwired to protect their family. So, it's less likely a family member will call the cops to report a son, daughter, or sibling.
The father in this case knew about all the problems his son was having, and about all the threats. Yet, he still enabled that behavior by keeping him out of jail and helping him buy guns.
Hindsight is 20/20. I bet there are thousands of other families just like this who think they are helping their family member by protecting them from the system lawmakers put in place to weed out the violent ones undeserving of the right to keep and bear arms.
So, what's the solution to these observers who don't want to red flag their own kin? These red flag laws are destined to fail at stopping violence, but they have, and they will, succeed at getting innocent people killed when the Cops show up to take their guns.