In the wake of any mass shooting, you’re going to hear calls for gun control. That’s especially true when an AR-15 was used since that’s the boogieman of the day.

Yet often, we don’t know enough to even speculate how the killers got their guns.

After a shooting at a St. Louis high school earlier this week, the debate resurfaced, as per usual. Also as usual, questions surfaced as to how the killer obtained his firearm in the first place.

Now, we have deeper questions.

Months before a 19-year-old shooter opened fire Monday inside a St. Louis high school, his family told police he had a gun and had it removed from the home, officials said Wednesday.

The family were aware the gunman had mental health struggles and did “everything that they possibly could have done” to help him —including getting him therapy and medication and committing him on several occasions — but “sometimes that’s not enough,” interim St. Louis Police Chief Michael Sack said at a news conference.

Police said that earlier this month, the gunman’s mother found an AR-15-style rifle in the family’s home and wanted it removed.

“While it is not yet clear when or how the suspect came to be in possession of the firearm after this incident, we can confirm that the firearm involved in this incident is the firearm used” at Central Visual and Performing Arts High School on Monday, police said in a statement Wednesday evening.

In other words, even after the family got involved and got the weapon out of the house, the killer somehow was able to get that exact same rifle back.

And yes, there are questions.

At the request of the family, the police facilitated the transfer of this weapon to a third party, someone known to the family but who could lawfully possess a firearm. The family seems like they understood they had a potential powder keg in the house and were trying to do just about everything they could to put a handle on things.

Yet despite that, he somehow was able to get that exact gun back, then use it to commit a school shooting.

It boggles the mind.

Let’s also recognize that what this family did was tantamount to using a red flag order. They removed the gun from the premises. Despite that, he was still able to get his hands on a firearm.

Now, in fairness, a red flag order would have yanked the gun from him and kept it in police custody, but it seems likely that someone didn’t think he was a threat and let him have access to a firearm. Why would it be any different after a red-flag seizure?

As for what happened in St. Louis, we have a lot of questions and they’re not going to get answered anytime soon. The shooter was killed at the scene, after all, so he won’t be answering any questions unless the investigators break out the Ouija board.

But while the debate on this subject is going to rage on for Lord only knows how long, it seems to me that this tells you that even if someone does everything right, someone else who is dead set on killing innocent people will find a way to do it.

Ban AR-15s? This guy could have done just as much damage with a pump-action shotgun. Keep people under 21 from buying firearms at all? It sure looks like someone handed this kid a gun after his family expressed concerns.

We have a problem, but the issue seems to stem from how little we know and understand these killers.