An 11-year-old boy shot and killed his teacher Friday at a school in northern Mexico and wounded six other people before killing himself, authorities said.
As shocked Mexicans searched for explanations for the school shooting -- a rare event for the country -- officials said they were investigating a possible link to the Columbine High School massacre in the US in 1999.
Panicked parents rushed to the private elementary school, the Colegio Cervantes, in Torreon as officials evacuated the trim brick building and police and soldiers put it on lockdown.
"We deeply regret this incident... which is shocking for us all," Governor Miguel Angel Riquelme of the state of Coahuila, which borders the United States, told a news conference.
"I want to reiterate that this sort of thing is not the norm in our schools."
He said his own daughters had attended the school, one of the oldest and most prestigious in Torreon, a city of 600,000 people.
- Columbine link? -
The shooter wore a T-shirt with "Natural Selection" written on it -- the same words seen on the shirt of one of the Columbine attackers two decades ago in Colorado.
But authorities said the phrase may also have been a reference to a first-person shooter video game called "Natural Selection" -- first released in 2002 and not directly related to Columbine.
The boy had talked to classmates about the game, said Riquelme.
"I believe he was trying to recreate" the video game in real life, said Riquelme.
The boy changed into the shirt in the bathroom at school, he added.
Addressing the question of a possible link with Columbine, state prosecutor Gerardo Marquez said: "We have to follow every possible line of investigation, and that is one of them."
When the boy's teacher, a 50-year-old woman, went to check on him because he had been gone unusually long, he opened fire in the hallway with two handguns, killing her, wounding five other students and a 40-year-old physical education teacher, and then killing himself.
The wounded were taken to a local hospital, where they were in stable condition, Riquelme said.
- Search for answers -
Mexico is more used to seeing school shootings in the neighboring United States than up close.
However, the incident was not without precedent.
In 2014, a 15-year-old shot and killed a schoolmate in central Mexico state, and in 2017, another 15-year-old shot and wounded four classmates at a high school in the northern city of Monterrey.
The Torreon student, who was in his final year of elementary school, lived with his grandparents and got good grades, officials said.
Riquelme said the boy had not shown behavioral problems, but had told classmates that "today was the day."
Whether intentional or not, the words "Natural Selection" carried haunting echoes of the Columbine shooting, when two students killed 13 schoolmates and then themselves.
One of the shooters wore a T-shirt with that phrase printed on it -- an apparent reference to Charles Darwin and his theory on how species evolve.
- Endemic gun violence -
Although school shootings are uncommon in Mexico, the country is all too familiar with gun violence, often linked to brutally violent drug cartels.
Mexico has registered nearly 275,000 murders since 2006, the year the government launched a controversial military offensive against cartels.
Authorities said they were investigating how the boy obtained his guns.
Relatives of schoolchildren gathered outside the elementary school in Mexico for news after a student shot and killed a teacher and wounded six others, and then apparently killed himself in Torreon
Map of Mexico locating attack on teacher by young child in torreon
A funeral van leaves the Mexican school where a student shot and killed a teacher