ADVENTURES IN TOXIC MEMES: For ‘Columbiners,’ School Shootings Have a Deadly Allure.

He wore a T-shirt with the phrase “Born to Kill” on it in bold, similar in design to those worn by the Columbine attackers, which read “Wrath” and “Natural Selection.”

His crude arsenal included canisters of carbon-dioxide gas and Molotov cocktails, two types of explosives used by the Columbine gunmen.

The picture he had posted of his trench coat on Facebook showed a small red-star medallion with the Communist hammer-and-sickle on the collar, the same type of button a Columbine gunman attached to his boot.

It was not the first time a high school suddenly engulfed in gunfire and death found itself looking for clues in the random symbology of a nearly 20-year-old mass shooting that has become, it seems, the standard by which youthful gunmen across America have come to measure themselves.

The 20-year-old attacker who killed 26 people at Sandy Hook Elementary School in Connecticut in 2012 had compiled an enormous mass-murder spreadsheet and materials on the Columbine attackers on his computer, including what appeared to be a complete copy of the official Columbine investigation.

In his manifesto, the 23-year-old student who shot and killed 32 people at Virginia Tech in 2007 had called the Columbine gunmen by their first names and described them as “we martyrs.”

The May 18 mass shooting at Santa Fe provides the latest evidence of a phenomenon that researchers have in recent years come to recognize, but are still unable to explain: The mass shootings that are now occurring with disturbing regularity at the nation’s schools are shocking, disturbing, tragic — and seemingly contagious. . . . The role of the media in turning school gunmen into household names and perpetuating “the infamous legacy they desire” can be shown to have inspired additional attacks, researchers at Western New Mexico University reported recently. . . .

Ms. Klebold, the mother of one of the Columbine attackers, said she was shocked by the number of letters she receives from people who relate to her son: “The girls who say, ‘I wish I could have his baby’”; others who say that her son, to them, is “heroic.” Even seeing images of the Santa Fe gunman’s Communist hammer-and-sickle medallion — just like the one that her son wore, a gift from a friend’s parent who went to Russia — was painful to her.

Plus: “It worries me that even now, kids who were not even born during Columbine High School are still making reference to Columbine.”

Related: Inoculating Ourselves Against The School Shooting Infection.

Flashback: NRA spokeswoman accuses media of ‘creating’ mass shooters with extensive coverage.