BUFFALO, N.Y. -- The white 18-year-old who fatally shot 10 people at a Buffalo supermarket researched the local demographics and arrived a day in advance to conduct reconnaissance with the intent of killing as many Black people as possible, officials said Sunday.
The racially motivated attack came a year after the gunman was taken to a hospital by state police after making threats involving his high school, according to authorities.
He wasn't charged with a crime and was out of the hospital within a day and a half, police said, but the revelation raised questions about his access to weapons and whether he could have been under closer supervision by law enforcement.
The Buffalo attack prompted grief and anger in the predominantly Black neighborhood around Tops Friendly Market. A group of people gathered there Sunday afternoon to lead chants of "Black lives matter" and mourn victims that included an 86-year-old woman who had just visited her husband in a nursing home, and a supermarket security guard, both of whom were Black.
"Somebody filled his heart so full of hate that he would destroy and devastate our community," the Rev. Denise Walden-Glenn said.
The Buffalo attack was the deadliest of multiple shootings across the country in recent days. Officials in Milwaukee imposed a curfew after 21 people were injured in three separate shootings near an entertainment district where thousands gathered Friday for an NBA playoff game.
As the country reeled from the Buffalo attack, new details emerged about the gunman's past and Saturday's rampage, which the shooter livestreamed on Twitch. New York Gov. Kathy Hochul, a Buffalo native, demanded technology companies tell her whether they've done "everything humanly possible" to make sure they're monitoring violent content as soon as it appears.
"If not, then I'm going to hold you responsible," she said.
Twitch said in a statement that it ended the transmission "less than two minutes after the violence started."
The New York State Police said troopers were called early last June to the high school then attended by the shooting suspect, Payton Gendron, for a report that a 17-year-old student had made threatening statements.
Gendron threatened to carry out a shooting at Susquehanna Valley High School, in Conklin, N.Y., around the time of graduation, a law enforcement official said. The official was not authorized to speak publicly on the investigation.
Buffalo Police Commissioner Joseph Gramaglia said Gendron had no further contact with law enforcement after his release from the hospital.
"Nobody called in," he said. "Nobody called any complaints," Gramaglia said.
Federal law bars people from owning a gun if a judge has determined they have a "mental defect" or they have been forced into a mental institution -- but an evaluation alone would not trigger the prohibition.
Federal authorities were still working to confirm the authenticity of a racist 180-page document, purportedly written by Gendron, that detailed his plans for the attack and reasons for carrying it out.
A preliminary investigation found Gendron had repeatedly visited sites espousing white supremacist ideologies and race-based conspiracy theories and extensively researched the 2019 mosque shootings in Christchurch, New Zealand, and the man who killed dozens at a summer camp in Norway in 2011, the law enforcement official told reporters.
Federal agents served multiple search warrants and interviewed Gendron's parents, who were cooperating with investigators, the law enforcement official said.
Portions of the Twitch video circulating online showed the gunman firing volley after volley of shots in less than a minute as he raced through the parking lot and then the store, pausing for just a moment to reload. At one point, he trains his weapon on a white person cowering behind a checkout counter, but says "Sorry!" and doesn't shoot.
Screenshots purporting to be from the broadcast appear to show a racial slur targeting Black people scrawled on his rifle, as well as the number 14 -- likely referencing a white supremacist slogan.
Authorities said he shot, in total, 11 Black people and two white people Saturday.
"This individual came here with the express purpose of taking as many Black lives as he possibly could," Buffalo Mayor Byron Brown said at a news conference Sunday.
The lengthy statement attributed to Gendron outlined a racist ideology rooted in a belief that the United States should belong only to white people. All others, the document said, were "replacers" who should be eliminated by force or terror. The attack was intended to intimidate all non-white, non-Christian people and get them to leave the country, it said.
The document said Gendron researched demographics to select his target, and picked a neighborhood in Buffalo because it had a high ratio of Black residents.
Gendron traveled about 200 miles from his home in Conklin to Buffalo to commit the attack, police said.
He conducted reconnaissance on the store and the area on Friday, a day before the shooting, Gramaglia said.
One analysis from the University of Michigan, based on data from the 2010 census, found that the Buffalo-Niagara Falls metro area was the nation's sixth most segregated when ranked specifically by the distribution of Black and white residents.
Segregation is also a root cause, according to experts, of why efforts to bring an economic renaissance to Buffalo have done little for Black residents. A University of Buffalo report in 2021 found that living conditions for Black residents of the city, across measures of health, housing, income and education, had improved little and in some cases had declined over the preceding 30 years.
India Walton, a nurse and community activist who nearly unseated Buffalo's four-term Democratic mayor last year, called the city "segregated by design" as she reacted to the shooting on Twitter.
"Our government can't prevent things that they actually cause," she wrote.
Gendron surrendered to police who confronted him in the supermarket's vestibule and persuaded him to drop the rifle he had put to his neck. He was arraigned later Saturday on a murder charge, appearing before a judge in a paper gown.
'OUR HEARTS ARE HEAVY'
President Joe Biden urged unity Sunday after the deadly mass shooting.
Addressing an annual law enforcement ceremony at the U.S. Capitol, Biden said he and his wife, Jill, pray for those who were shot "by a lone gunman, armed with weapons of war and hate-filled soul," and their families.
"We must all work together to address the hate that remains a stain on the soul of America," Biden said at the 41st annual National Peace Officers' Memorial Service honoring fallen law enforcement officers. "Our hearts are heavy once again, but the resolve must never, ever waver."
"No one understands this more than the people sitting in front of me," he added. The White House said the Bidens would travel to Buffalo on Tuesday to grieve with the community.
Biden, speaking at the ceremony for the second time as president, did not address the calls by New York officials -- Gov. Hochul and Mayor Brown -- for strong federal action to end what Brown said is the "uniquely American phenomenon" of mass shootings.
The president also did not mention gun control efforts that have stalled in Washington.
Brown expressed frustration that "thoughts and prayers" and pledges to act are offered after every mass shooting, only to be be blocked by "some on one side of the aisle."
"It seems like there are those that believe owning a gun is more precious than the sanctity of human life," the mayor told NBC's "Meet the Press." "So I think people all across this country have to rise up. They have to speak more loudly and more clearly that there must be gun control in this country. This is a uniquely American phenomenon. These mass shootings don't happen in other countries across the world."
Brown said he would like to see "sensible gun control."
House Speaker Nancy Pelosi, D-Calif., said tighter gun measures are "a huge priority" for Democrats and the White House. She bemoaned the 60-vote threshold needed in the 50-50 Senate that has made it difficult to advance such legislation, but she pledged on CNN's "State of the Union" that "we are not going away until the job is done."
Hochul said most of the illegal guns being used on the streets of her cities come from other states. "We need a national response," she told NBC.
"We need other states to step up. We need the federal government on our side," said Hochul, a Buffalo native.
Information for this article was contribued by Carolyn Thompson, Michael Balsamo, Robert Bumsted, Michael Hill, Darlene Superville, Travis Loller and Jake Bleiberg of The Associated Press and by Anushka Patil of The New York Times.
Flowers and candles lay outside the scene of a shooting at a supermarket, in Buffalo, N.Y., Sunday, May 15, 2022. (AP Photo/Matt Rourke)
Payton Gendron appears during his arraignment in Buffalo City Court, Saturday, May 14, 2022, in Buffalo, N.Y. Gendron was arraigned on first-degree murder charges and ordered detained without bail. Police officials said the 18-year-old was wearing body armor and military-style clothing when he pulled up and opened fire at people at a Tops Friendly Market. (Mark Mulville/The Buffalo News via AP)
A person holds a flower as a group prays outside of the scene of a shooting at a supermarket in Buffalo, N.Y., Sunday, May 15, 2022. (AP Photo/Matt Rourke)
People hug outside the scene after a shooting at a supermarket on Saturday, May 14, 2022, in Buffalo, N.Y. (AP Photo/Joshua Bessex)
People pay their respects outside the scene of a shooting at a supermarket in Buffalo, N.Y., Sunday, May 15, 2022. (AP Photo/Matt Rourke)
A person walks past the scene of a shooting at a supermarket, in Buffalo, N.Y., Sunday, May 15, 2022. (AP Photo/Matt Rourke)
This photo dated Oct. 24, 2011 shows Katherine Massey walking near the corner of Elmwood and Tupper in Buffalo, N.Y. Massey was one of the victims killed in the grocery store shooting in Buffalo on Saturday. Her sister calls her "a beautiful soul." {Robert Kirkham/The Buffalo News via AP)
Children walk hand in hand out near the scene of a shooting at a supermarket in Buffalo, N.Y., Sunday, May 15, 2022. (AP Photo/Matt Rourke)
People march to the scene of a shooting at a supermarket in Buffalo, N.Y., Sunday, May 15, 2022. (AP Photo/Matt Rourke)Gallery: Day after Buffalo market mass shooting
