A teenage gunman entranced by a white supremacist ideology known as replacement theory opened fire at a supermarket in Buffalo on Saturday, methodically shooting and killing 10 people and injuring three more, almost all of them Black, in one of the deadliest racist massacres in recent American history.
The authorities identified the gunman as 18-year-old Payton S. Gendron of Conklin, a small town in New York’s rural Southern Tier. Mr. Gendron drove more than 200 miles to mount his attack, which he also livestreamed, the police said, a chilling video feed that appeared designed to promote his sinister agenda.
Shortly after Mr. Gendron was captured, a manifesto believed to have been posted online by the gunman emerged, riddled with racist, anti-immigrant views that claimed white Americans were at risk of being replaced by people of color. In the video that appeared to have been captured by the camera affixed to his helmet, an anti-Black racial slur can be seen on the barrel of his weapon.
In the Buffalo grocery store, where four employees were shot, the savagery and planning were evident: Mr. Gendron was armed with an assault weapon and wore body armor, the police said. And his preferred victims seemed clear as well: All told, 11 of the people shot were Black and two were white, the authorities said.
“It was a straight up racially motivated hate crime,” John Garcia, the Erie County sheriff, said.
In a news conference Saturday evening, Gov. Kathy Hochul — a Buffalo native — echoed that sentiment and decried the attack as an “act of barbarism” and an “execution of innocent human beings,” as well as a frightening reminder of the dangers of “white supremacist terrorism.”
“It strikes us in our very hearts to know that there is such evil that lurks out there,” Governor Hochul said.
Based on what was written in the manifesto, the attack appeared to have been inspired by earlier massacres that were motivated by racial hatred, including a mosque shooting in New Zealand and the Walmart shooting in Texas, both in 2019.
In the manifesto, which was being reviewed by law enforcement, Mr. Gendron — who had attended a community college in Binghamton, N.Y. — wrote that he had selected the area because it held the largest percentage of Black residents near his home in the state’s Southern Tier, a predominantly white region that borders Pennsylvania.
The document outlined a careful plan to kill as many Black people as possible, complete with the type of gun he would use, a timeline, and where he would eat beforehand.
It also included details of where he would livestream the violence, mayhem that he had also calibrated. He carefully studied the layout of the grocery, writing that he would shoot a security guard before stalking through aisles and firing upon Black shoppers. He wrote that he would shoot some twice, in the chest, when he could.
When Buffalo police officers arrived and confronted Mr. Gendron, he put a gun to his neck, but two patrolmen persuaded him to drop his weapon and surrender, Mr. Gramaglia said.