The white man who carried out a racist attack at a supermarket in Buffalo was indicted by a grand jury on Thursday. Payton Gendron was accused of killing 10 Black people.

The 18-year-old appeared in court wearing an orange jail uniform, a mask and handcuffs. As the proceedings began, someone from the courtroom gallery shouted: “Payton, you’re a coward!”

Assistant district attorney Gary Hackbush said the first-degree murder indictment, which covers all 10 deaths, was handed up Wednesday.

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Thirteen people were shot Saturday at the Tops Friendly Market in a predominantly Black neighborhood. The incident is being investigated as a possible hate crime.

The victims’ family members were also present at the hearing.

On Saturday, Gendron went on a shooting rampage and livestreamed the attack from a helmet camera. Shortly before the attack, he posted hundreds of pages of writings to online discussion groups where he detailed his plans for the assault. His racist motivation was also highlighted in the posts.

All but two of the 13 people shot during the attack were Black.

New York Governor Kathy Hochul on Wednesday authorised the state’s attorney general, Letitia James, to investigate social media platforms used by Gendron. The probe would help determine if they were liable for “providing a platform to plan and promote violence.”

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President Joe Biden, in a visit to Buffalo on Tuesday, condemned the horrific attack.

“What happened here is simple and straightforward: terrorism, terrorism, domestic terrorism,” Biden said.

New York Gov. Kathy Hochul told CNN that the suspect was “on the radar” of law enforcement.

“Just as a high school student with respect to something he wrote in high school and was under surveillance at the time with medical authorities,” she said.