The alleged deranged mass shooter who shot and killed 10 people in a “racially motivated” rampage in a Buffalo supermarket faced a judge hours after the Saturday afternoon massacre.

Payton Gendron, 18, of Conklin, New York, wore a white paper gown and mask and was surrounded by police officers at his Saturday evening arraignment in Buffalo City Court, according to WKBW-TV.

Gendron was stoic as his court-appointed lawyer pleaded not guilty to first-degree murder charges on his behalf, the station said.

He was reportedly remanded without bail and due back in court on Thursday.

Gendron allegedly killed 10 people and injured three others at a Tops grocery store in a predominantly black neighborhood around 2:30 p.m. Eleven of the victims were black and two were white.

He had driven some 200 miles from his home near Binghamton to carry out the sick mass shooting and was heavily armed and wearing tactical gear, officials said.

The shooting began in the supermarket parking lot and continued in the store, before he was taken into custody by Buffalo police.

“This was pure evil. It was a straight-up racially motivated hate crime from somebody outside of our community, outside of the City of Good neighbors … coming into our community and trying to inflict that evil upon us,” Erie County Sheriff John Garcia said at a press conference.

The FBI was investigating the incident as both “a hate crime and a case of racially-motivated violent extremism,” Special Agent Stephen Belongia said.

“The depth of pain that families are feeling and that all of us are feeling right now cannot even be explained,” Buffalo Mayor Byron Brown said.