The authorities in Mexico are still piecing together how a typical morning at the ancient pyramid complex of Teotihuacán, one of the country's foremost tourist destinations, descended into terrifying gun violence on Monday.

The video footage is disturbing. A gunman stands atop the imposing Pyramid of the Moon and opens fire on the tourists around him, who cower for cover among the pre-Hispanic stone structures.

After the ordeal, a 32-year-old Canadian woman had been killed and the gunman had died from a self-inflicted gun wound. Tourists from several nations, including Russia, Colombia, and Brazil, were treated for their injuries in local hospitals.

The fact that visitors from overseas were targeted poses a headache for the government just weeks before Mexico co-hosts the men's football World Cup.

The shooting came less than two months after masked gunmen from the Jalisco New Generation Cartel unleashed violence across the country following the killing of their leader El Mencho. But this incident was very different.

Mexican authorities say the Teotihuacán gunman acted alone and there was no apparent link to Mexico's widespread cartel violence.

He has been identified as 27-year-old Julio César Jasso Ramírez, a Mexican citizen who lived in Mexico City.

The Attorney-General of Mexico State, José Luis Cervantes Martínez, stated that the aggressor acted independently, with no indication of external help or involvement from others.

Among the gunman's belongings, officials found a handgun, a bag of cartridges, and a tactical knife, along with disturbing literature and references to the Columbine school shooting.

Mexicans are no strangers to violence, but this shooting appears to fall into a different category, one of mass killings conducted by lone assailants without ties to organized crime.

Valeria Villa, a Mexican family therapist, noted that such incidents signal a troubling trend toward imitation of mass killings prevalent in the US, exacerbated by Mexico's ongoing issues with violence.

Even as President Claudia Sheinbaum reassures citizens and visitors about safety, the haunting image of a gunman firing from the pyramid is a stark reminder of the work that remains to restore confidence in public safety leading up to the World Cup.