BUFFALO, NY - MAY 14: Buffalo Police on scene at a Tops Friendly Market on May 14, 2022 in Buffalo, New York. According to reports, at least 10 people were killed after a mass shooting at the store with the shooter in police custody. (Photo by John Normile/Getty Images)

BUFFALO, N.Y. (AP) — Law enforcement officials say the white 18-year-old gunman who shot and killed 10 people at a Buffalo supermarket had researched the local demographics while looking for places with a high concentration of Black residents, arriving there at least a day in advance to conduct reconnaissance. Authorities said Payton Gendron shot, in total, 11 Black people and two white people Saturday in a rampage motivated by racial hatred that he broadcast live. He has been arraigned on a murder charge. A law enforcement official told The Associated Press that federal authorities were still working to confirm the authenticity of a 180-page manifesto that detailed the plot and identified Gendron.