Dylan Klebold wielded an Intratec TEC-DC9, an assault weapon originally conceived as a machine gun for South African police.

His friend, Eric Harris, carried a Hi Point 995, a cheap short-barreled rifle.

Both also brought shotguns sawed off to spray ammunition widely.

Together they fired 188 rounds at Columbine High School, killing 12 classmates and a teacher and wounding 21 with gunfire. Then they shot themselves.

At the time, it was the deadliest school shooting in U.S. history.

In 2012, James Holmes attached a 100-round ammunition magazine bought on the internet to an AR-15 semi-automatic rifle, the gun most often used in U.S. mass shootings.

Holmes fired 76 rounds from three guns, killing 12 people and a pregnant woman’s baby at a “Batman” movie showing in Aurora. He injured 70, 58 from gunfire.

A graduate student, he was seeing a campus psychiatrist at the time of the massacre.

At the time, it was the deadliest shooting by a lone gunman in U.S. history.

Now Colorado is reeling from two more mass shootings in less than two months.

In Boulder County, Ahmad Al Aliwi Alissa faces a murder trial for killing 10 people at a crowded King Soopers on Mar. 22. All were murdered with a Ruger AR-556 pistol, a gun similar to the AR-15 rifle.

Despite a Colorado law limiting gun magazines to 15 rounds after the movie theater massacre, he somehow brought 10 30-round magazines from his home to Boulder.

On Mother’s Day, 28-yearold Teodoro Macias allegedly shot and killed six people at a birthday party in Colorado Springs, including his girlfriend.

Police said he murdered them with a Smith & Wesson semi-automatic pistol, then killed himself, angry that he wasn’t invited to the party.

The Gazette found that the deadliest shootings in Colorado have been committed by men firing randomly at people in crowded places. Motives varied, but in case after case, the killers showed signs of mental illnesses and made threats in advance.

They also shared two other things: a crazed indifference to human life and arsenals of assault weapons.

Together they have given Colorado an image no state wants, as a mecca of civilian massacres.

A Gazette analysis of eight mass shootings from Boulder to Colorado Springs found the killers all wielded semi-automatic weapons, usually with high-capacity magazines that allowed them to fire 30 or more rounds without reloading.

Of 10 perpetrators involved in the eight shootings, five were teenagers. Only one was older than 28. All were males.

State Rep. Tom Sullivan, who lost his son Alex in the Aurora movie theater massacre, told a legislative committee last week that Colorado has gained an international reputation for gun violence.

“Recently, we had a Japanese TV crew in our kitchen,” he said, who wanted to know why scenic Colorado suffers such ugly rampages. “I am as puzzled as they are.”

Most of these shooters were young, seemingly intelligent white males.

In 1993, Nathan Dunlap took revenge on a Chuck E. Cheese arcade that had fired him.

He played a few games, then hid in the restroom until closing time.

He came out with a .25 caliber semi-automatic pistol, shooting five employees. Four died.

Dunlap was 19, the son of a woman who battled extreme mental illnesses. At the age of 15, he was locked up in a juvenile detention center for his involvement in armed robberies and had spent time in a psychiatric hospital.

In 2007, 24-year-old Matthew Murray murdered people in church groups in Arvada and Colorado Springs. First he killed two people and wounded two at a Youth With A Mission Center in Arvada. In Colorado Springs, he killed two people and injured three before a New Life Church safety official shot and wounded him. Then he shot himself in the head.

In 2019, two boys at a Douglas County STEM school smashed a parent’s gun safe and came to class with weapons concealed in guitar cases.

Devon Erickson, 18, and Alec Mckinney, 16, possessed a Glock semi-automatic pistol, a Beretta semi-automatic pistol, a Ruger semi-automatic rifle and a Taurus revolver.

Erickson killed a classmate who tried to stop him. Mckinney wounded eight in the middle school area.

Both had exhibited symptoms of mental illnesses and made threats before they shot children.

In 2015, Robert Lewis Dear, a 57-year-old anti-abortion fanatic, attacked a Planned

Parenthood clinic in Colorado Springs with an SKS semiautomatic rifle, killing three people and wounding nine.

Dear was obsessed with the idea of a coming apocalypse and called himself a warrior for the babies.

In court, he was found to be delusional and incompetent to stand trial. The judge sentenced him to a state mental hospital.

Tragically, Colorado’s two latest shooting sprees mirror a national trend. Gun purchases escalated during the COVID pandemic and, this year, mass shootings have become a weekly occurrence in the United States.

From Colorado to Congress, debates over gun laws have remained bitterly divided.

Republicans defend their Second Amendment rights, fearing gun controls will lead to bans and ultimate confiscation.

Democrats, meanwhile, have also become wary of restricting those rights.

Many believed Al Gore lost his home state of Tennessee and the 2000 election because he favored stricter gun laws.

In Colorado, Republican Gov. Bill Owens and Democratic U.S. Senator Ken Salazar spearheaded a successful voter initiative in 2000 to require background checks at gun shows, where Klebold and Harris had armed themselves to murder classmates at Columbine High.

But by 2013, a political chasm over gun ownership had hardened.

Democratic legislators paid a price for limiting gun magazines to 15 rounds and expanding background check requirements in response to the Aurora shooting.

Two Democratic legislators were recalled, and a third resigned to avoid the same fate.

This year, Colorado Democrats have advanced proposals — safe gun storage, mandatory reporting of gun thefts, adding violent misdemeanors as prohibitions.

A bill to create a state Office of Gun Violence Prevention provoked a five-hour debate that left some Democratic legislators in tears while Republicans sat in stoic opposition.

Held before the bulkily named Public and Behavioral Health & Human Services Committee, the hearing concluded with straight party line votes. All eight Democrats voted yes, sending a $3 million measure to Appropriations. All five Republicans opposed it.

One Republican, retired teacher Mary Bradfield, initially announced she would support the bill.

Minutes later, she apologetically changed her mind, saying her legislative aide had informed her that her constituents opposed it.

Bradfield represents El Paso County District 21, which includes Fountain.

In an interview Wednesday, she said the Mother’s Day shooting did not affect her opinion.

“The issue we have is not the firearms,” she said. “It’s mental health.”

Republican Rep. Richard Holtorf, a rancher from rural Akron, rested a cowboy hat beside him as he explained at the hearing that people on the Eastern plains view a gun as “a tool in a toolbox.”

Calling himself a country boy determined to protect their Second Amendment rights, he expressed sympathy for families devastated by gun violence. But he questioned whether a gun violence office would grow into a vehicle for new gun ownership restrictions.

He “respectfully” voted no. The Firearms Coalition of Colorado, an NRA affiliate, objected to the name of the proposed office, calling it “a pejorative term that casts aspersions on all persons who use firearms for lawful purposes, including self-defense.”

Proponents made emotional pleas.

Maisha Fields, the daughter of State Sen. Rhonda Fields of Aurora, rapped the witness table loudly, twice.

“I am a member of a club that nobody wants to be a part of,” she said.

The knock on her door came when she was a nursing student in California.

Her brother, Javad Marshall-fields, was the key witness in a murder case. Nobody had thought to make him a protected witness or deprive the accused killers of guns. One, Sir Mario Owens, sprayed more than a dozen bullets into her brother’s car on an Aurora street, killing him and his fiancee.

Today she works for the Brady anti-gun violence coalition and praises Colorado for at least moving to study its gun violence.

“We cannot change what we don’t understand,” she said.

Rep. Sullivan urged his colleagues to make Colorado a national model in that respect.

“Folks, we have a gun violence problem in our state,” he said.

In recent years, public health researchers have emerged as a perceived leading threat by gun enthusiasts.

One is James Densley, co-founder of The Violence Project. He criticizes the United States for defunding mental health programs when so many mass shootings are committed by mentally ill young men.

He wishes governments would make it easier to reach a crisis line when a family member is acting crazy with a gun.

“It’s really difficult for a mom to call the cops on her own child,” he said.

Densley suggested that the Columbine High massacre might help explain why Colorado keeps mourning the carnage left by others who turned suicidal despair into killing sprees.

“Columbine is so etched in the collective memory of the community that it will never go away,” he said. “I think there is a collective trauma. In our research, we see that mass shooters study other mass shooters.”

Assault weapon sales were banned in the United States from 1994 to 2004, a period when mass shooting deaths plummeted. The notable exception was 1999, the year of the Columbine High massacre.

Elsewhere in the world, assault weapons have been banned, even confiscated, in response to a single massacre.

The United States relies on a patchwork of laws and rules that vary immensely from state to state.

The numbers of people forbidden to buy guns because of mental illnesses, for instance, ranged from 718,334 in Pennsylvania to three in Wyoming and Montana and one in Alaska and Massachusetts, according to a 2016 study reported by the New York Times.

Colorado had submitted 51,900 records to the national background check system. It also requires background checks on gun sales.

Its neighboring states don’t. While the locations of deadly shootings have ranged from churches and supermarkets to corporate and police offices, and from elementary schools to colleges, one factor remained constant.

Of 122 mass shootings from 1982 to April in the United States, 118 were carried out by males.

Two months after Alissa allegedly murdered 10 people at a Boulder King Soopers, questions loom large.

How did he get 10 large capacity magazines, all illegal to buy or sell in Colorado?

Why did he drive 20 miles to Boulder when there was a King Soopers directly across the street from the gun store in Arvada where Alyssa allegedly bought his gun?

The Boulder district attorney has not implicated the Eagles Nest Armory, and its owner, John Mark Eagleton, declined to answer a reporter’s questions about the alleged sale.

“All of these topics remain a focus of the investigation,” said Shannon Carbone, a spokeswoman for the Boulder district attorney.

Rep. Sullivan suggested three possibilities: Alissa could have bought them on the internet, from a corrupt Colorado dealer or from a gun store in Wyoming.

Rep. Judy Amabile, of House District 13 which includes parts of Boulder, a sponsor of the gun violence prevention office bill, said Alissa’s family probably didn’t know that Colorado has a red flag law permitting the temporary seizure of guns from a mentally disturbed owner.

Her sponsorship stems from a mental health crisis in her own family.

Her son went to buy a gun when he was 25, intending to kill himself. She found out and stopped the sale.

“He was waiting to buy the gun,” she said. “If his background check had come back, he’d be dead now.”

She hopes that a well-publicized gun violence prevention office will help other mothers share her good fortune.

“We need to be talking about our violent culture,” she said. “It should be easier to see a psychiatrist than to buy a gun.”

Her son is 28 now.