NEW YORK, United States (AP) — The white gunman accused of massacring 10 Black people in a racist rampage at a Buffalo supermarket planned to keep on killing if he had escaped the scene, the police commissioner said Monday, as the possibility of federal hate crime or domestic terror charges loomed.

The gunman, who had crossed the state to target people at the Tops Friendly Market, had talked about shooting up another store as well, Buffalo Police Commissioner Joseph Gramaglia told CNN.

“He was going to get in his car and continue to drive down Jefferson Avenue and continue doing the same thing,” the commissioner said.

The commissioner’s account was similar to portions of a racist 180-page document, purportedly written by Payton Gendron, that said the assault was intended to terrorize all nonwhite, non-Christian people and get them to leave the country. Federal authorities were working to confirm the document’s authenticity.

Gendron, 18, travelled about 200 miles (320 kilometers) from his home in Conklin, New York, to commit the attack, police said. Authorities said he wielded an AR-15-style rifle, wore body armor and used a helmet camera to livestream the bloodbath on the internet.

He was arraigned on a murder charge over the weekend and pleaded not guilty. Federal prosecutors said they are contemplating hate crime charges.

Former Buffalo Fire Commissioner Garnell Whitfield Jr, who lost his 86-year-old mother, Ruth Whitfield, in the shooting, asked how the country could allow its history of racist killings to repeat itself.

“We’re not just hurting. We’re angry. We’re mad. This shouldn’t have happened. We do our best to be good citizens, to be good people. We believe in God. We trust Him. We treat people with decency, and we love even our enemies,” Whitfield said at a news conference with civil rights attorney Ben Crump and others.

“And you expect us to keep doing this over and over and over again — over again, forgive and forget,” he continued. “While people we elect and trust in offices around this country do their best not to protect us, not to consider us equal.”

Whitfield’s mother was killed after making her daily visit to her husband in a nursing home.

“How do we tell him that she’s gone? Much less that she’s gone at the hands of a white supremacist? Of a terrorist? An evil person who is allowed to live among us?” Whitfield said.

The victims also included a man buying a cake for his grandson; a church deacon helping people get home with their groceries; and a supermarket security guard.

The bloodshed in Buffalo was the deadliest in a wave of weekend shootings, including at a California church and a Texas flea market.

Messages were left with Gendron’s attorneys Monday. No one answered the door at his family’s home in the morning, and relatives did not respond to messages.