Complex problem

On July 22, 2011, Anders Behring Breivik dresses in a police uniform, loads a van with home-made explosives, and drives to Regjeringskvartalet, the executive government quarter in Oslo, Norway. He leaves the van outside the office of Prime Minister Jens Stoltenberg. Moments later, it explodes, causing several casualties.
On the island of Utøya in Tyrifjorden, Buskerud, teenagers have arrived for Workers' Youth League (AUF) summer camp, organized by the ruling Labour Party. When they learn of the bombing, one student, Viljar Hanssen, calls his parents to make sure they are unhurt.
Breivik arrives at the ferry landing and informs staff that he is a police officer, sent to secure the island following the attack in Oslo. The camp director transports him to the island by boat. Breivik instructs the staff to gather the children in one location. When the head of security asks for ID, Breivik shoots him and the director dead. The children flee as Breivik opens fire, murdering dozens.

On May 24, 2022 nineteen children and two adults were killed in a shooting at Robb Elementary School in Uvalde County on Tuesday, making the massacre the deadliest school shooting in Texas’ history.
Apart from the guns used being similar in these two mass murder events, the perpetrators had a lot in common as well: Young men alienated from society over a long period before turning violent.

The gun regulations in the US and Norway are vastly different, but neither perpetrator had any difficulty in acquiring the hardware needed for their enterprises.

And the signs were there for a long time before the mass murders took place. So maybe we need to take more interest in our fellow human beings in order to minimize explosive events like these?