“He was on our radar.”

How many times have we heard that after a mass shooting at a high school or a shopping mall?

We heard it for the umpteenth time again this week after a disturbed 14-year-old kid in Georgia took a rifle to school and killed two students, two teachers, and injured nine others.

“He was on our watch list,” the local police said to no one’s surprise.

A year ago, after the FBI’s radar picked up Colt Gray reportedly making threats online that he was going to “shoot up a middle school tomorrow,” the feds tipped off the county sheriff.

Colt and his father, Colin Gray, were questioned about the anonymous and unsubstantiated tip.

Colt assured a county investigator “he never made any threats to shoot up any school.”

His dad told the investigator that Colt had mental issues, but he was a good kid who’d never even joke about doing a terrible thing like that.

His dad also assured the police that though he had hunting rifles in the house, Colt did not have unfettered access to them.

The investigator said that he urged Colt’s father last year “to keep his firearms locked away and advised him to keep Colt out of school until this matter could be resolved.”

Case closed – until the tragedy of this week.

Colt was not kept out of school. His dad failed to prevent him from getting his hands on a rifle – and in fact, gave Colt the AR-15-style rifle he used in the shooting as a Christmas present months after he was visited by the investigators.

The police “radar” failed to stop the shooter – again. And four innocent people are dead.

Realistically, there’s not a lot that parents can do to “fix” a child like Colt, who has serious mental troubles and is a potential threat to others.

Parents can admit the truth and not be afraid of being shamed as a “bad parent.” They can seek professional care or put their child in a mental health facility, though when he turns 18, he has the right to get out.

But there is something very important that sensible and caring parents can do to prevent or reduce the number of future mass shootings.

It’s really not complicated. It’s simply putting the family’s pistols and rifles in a gun safe and making sure your kids don’t have the access code.

Even better, it’s getting all of your guns completely out of the house by giving them to a relative or friend to hold for you until your child grows up, gets control of his brain and stops being mad at the world.

Unfortunately, irresponsible or clueless gun-owning parents like Colt Gray’s father are not rare. They play a role in so many mass shootings that prosecutors and the courts are starting to make them pay for their carelessness.

Earlier this year a Michigan couple became the first parents convicted in a mass school shooting.

Because they missed so many chances to prevent their disturbed 15-year-old son from getting a handgun and killing four schoolmates in 2021, they were sentenced to 10 years in prison for involuntary manslaughter.

As the AP said, they were guilty of failing to secure a “newly purchased gun at home and acting indifferently to signs of their son’s deteriorating mental health.”

And Thursday night, as this was being written, the Georgia Bureau of Investigation charged Colt Gray’s father Colin with second degree murder and involuntary manslaughter “for knowingly allowing his son Colt to possess a weapon.”

Parents can play an important role in preventing tragic shootings like the one this week – which would never have happened if our “radar” worked the way it should – by knowing when to take their children’s guns away.

They should do their own “gun control” before the government tries to use mass shootings as an excuse to take all our guns away.

Michael Reagan, the son of President Ronald Reagan, is an author, speaker and president of the Reagan Legacy Foundation.