The first inkling that New Mexico state Rep. Pamelya Herndon (D) had that a fatal school shooting had just unfolded near her Albuquerque field office came as helicopters hovered overhead and police shouted from loudspeakers that everyone in the area should take shelter.

Within days, she learned that the 13-year-old boy charged with taking the life of another 13-year-old boy in August had been armed with his father’s gun — which prosecutors say was kept unsecured in the family home.

In response, Herndon began working on a bill that would require gun owners to keep their weapons locked up — or face criminal charges if a child took a firearm and used it in the commission of a crime.

“A law without penalties is simply a suggestion,” said state Sen. Daniel Ivey-Soto (D), who is working on a companion bill to be introduced in January. “We lost two children the day of the shooting. One is no longer with us; the other’s life will never be the same.”

If the bill passes, New Mexico will join 30 other states and the District of Columbia in having similar statutes, known as child access prevention laws.

In Michigan, where 15-year-old Ethan Crumbley on Tuesday allegedly shot and killed four of his Oxford High School classmates and wounded seven people, a safe-storage law was introduced last spring in the state legislature but stalled because of a lack of support. That could change in the wake of the shooting, with a state legislator now pushing for new consideration and Michigan Attorney General Dana Nessel (D) backing the move.

Even without the law, on Friday, the prosecutor handling the Oxford case announced her decision to file four counts of involuntary manslaughter against Crumbley’s parents, saying, “While the shooter was the one who entered the high school and pulled the trigger, there were other individuals who contributed to the events.”

Charging parents is unusual in a school shooting. A Washington Post review of 145 school shootings committed by children in the two decades after the Columbine High School massacre in 1999 found that the weapon’s source had been publicly identified in 105 cases. In total, the guns those children used were taken from their own homes or those of relatives or friends 80 percent of the time.

However, in just four instances did the adult owners of the weapons face any criminal punishment for not having locked them up — and none of those prosecutions stemmed from safe-storage laws.

Michigan state Sen. Rosemary Bayer (D), who introduced a safe-storage bill last spring, said she will resume pushing for its passage when the legislature reconvenes in January.

A Post analysis found that such measures could have a profound impact, since more than half of the country’s school shootings since 1999 could have been prevented if the children who killed their classmates did not have access to firearms. And an academic study found that the number of gun-related accidental deaths and suicides among children and teenagers would drop by as much as a third.

One reason for the dramatic drop is that in gun-owning households with children, about 2 in 10 gun owners store at least one firearm in the least safe manner — loaded and unlocked. That would represent 5 million minors living in houses with unsecured guns.

Bayer said her fellow lawmakers may now agree with her belief that a safe-storage law is needed in Michigan because of the student deaths and the resulting community trauma that has followed the Oxford High School shooting.

“This common-sense law may have prevented this shooting,” Bayer said. “We have met resistance on gun measures in the past, but we must take action this time. It’s time we come together and implement real solutions.”

Herndon, the New Mexico legislator, said she has faced similar difficulties and is frustrated that it may take a fatal school shooting in her state and now in Michigan to secure interest in the measure.

“I’ve tried two different times to get similar bills passed, but neither time was it after a tragic incident, not like it is this time, just months after a death at a local school,” Herndon said. “It’s sad, but I do think that will make a difference, as well as the shooting at the Michigan school.”

The National Rifle Association did not respond to a request for comment about the bills. Although the group instructs its members on ways to safely store firearms, the NRA has routinely lobbied against laws proposed to prevent child access to guns, saying such restrictions make lawfully owned guns “legally useless.” Despite the organization’s claim, online retailers sell dozens of reasonably priced pistol safes that can be accessed in seconds by gun owners who want to quickly reach their firearms in emergencies.

Still, dozens of states have passed such legislation, often with bipartisan support. Unlike other gun control measures, safe-storage laws do not restrict the number or type of firearms a person may own. And the bills focus explicitly on ways to keep children safe.

Although Congress passed a law in 2005 that requires gun manufacturers and dealers to include a secure gun storage or locking device in each sale or transfer of a handgun, federal law does not require that gun owners use those devices, according to Giffords Law Center to Prevent Gun Violence, an organization founded by former congresswoman Gabrielle Giffords (D-Ariz.) that advocates for tighter gun regulations.

That is why some state legislatures have stepped in to make safe storage a legal requirement, and gun safety groups say the need for such laws has never been greater — particularly as school shootings increased sharply after schools reopened this year.

There have been more school shootings in 2021 — 34 — than in any year since at least 1999, according to a Post database.

“When adults don’t prevent their children from accessing guns, this is the sort of devastation that can happen,” said Shannon Watts, founder of Moms Demand Action, part of Everytown for Gun Safety.

Although dozens of states have passed safe-storage laws, 20 have no such laws. And even in states where bills have passed, researchers say, they are often not enforced and carry weak penalties, rendering them far less effective than they could be.

Russ Hauge, a former Washington state prosecutor, has seen firsthand that even in cases of extreme negligence, gun owners often face no criminal punishment.

In 2012, a third-grader, he said, found a .45-caliber semiautomatic handgun in the home of his mother’s boyfriend, Douglas L. Bauer, who kept firearms — loaded, unlocked and in some cases cocked — throughout the place. The boy, then 9, put the weapon into his backpack and took it to school, where it accidentally fired, leaving a bullet lodged near the spine of an 8-year-old girl.

The prosecutor, whose state did not pass a safe-storage law until 2019, knew he could charge Bauer with reckless endangerment, he said, but a misdemeanor wouldn’t strip him of the right to own a gun, so Hauge charged him with third-degree assault, a felony.

Hauge argued that Bauer’s actions fit the definition of “criminal negligence” that “causes bodily harm to another person by means of a weapon.” The state Supreme Court, however, disagreed, deciding that the law was too vague to sustain the charge.

The law Washington state enacted in 2019 would have made all the difference in Bauer’s case, he said, because it subjects people to felony punishment if their failure to lock up guns leads to someone else’s injury or death. “Certainly, I think in my case, if we’d had a clear statute on the books, we could have prosecuted it as a felony,” he said.

Hauge, who left office in 2014, said he owns several firearms and is a firm supporter of the Second Amendment, but he said believes just as strongly that every state should require gun owners to secure their weapons.

“If there was a clear law that says felony punishment will ensue if you don’t handle your weapons safely,” Hauge said, “I think we could get some people’s attention.”

Alice Crites contributed to this report.