BUFFALO, N.Y. — Avowed white supremacist Payton Gendron appeared in court Thursday where he faced the relatives of some of the 10 he is charged with slaughtering in a Buffalo supermarkert – getting heckled as a “coward” as he was led out in shackles.  

The 18-year-old kept his eyes trained on the floor and was surrounded by a mass of deputies as he was brought into Buffalo City Court in an orange jumpsuit and chains around his feet and hands. 

“Payton, you’re a coward!” a woman shouted from the gallery where loved ones of some of the 10 killed in Saturday’s shooting got to see the teen suspect in person for the first time.

Gendron, who wore a white, cloth face mask, did not react and remained silent throughout the hearing that lasted mere minutes. 

Judge Craig Hannah remanded Gendron into custody and adjourned the hearing after a grand jury indicted him on a first-degree murder charge.

The Erie County District Attorney’s Office declined comment pending further action from the grand jury, which could come in the form of upgraded domestic extremism and hate crime charges. 

The justice set the next hearing date for June 9.

Prior to the hearing, a court officer confirmed to The Post that they had “beefed up” security as a mass of press from local, national and international media descended on the courthouse. 

Following an initial screening, reporters were wanded by court officers and their belongings were taken to a separate room to be sniffed by a K9 before the scribes were permitted to enter the basement courtroom where Gendron’s hearing was held. 

The suspect was busted Saturday in camouflage and body armor at the scene of the slaughter, which is about 200 miles from his Conklin, NY home.

He live-streamed the hate-fueled massacre using a camera affixed to his military-grade helmet – items he spent months procuring and perfecting ahead of the attack. 

The AR-15-style weapon used in the attack was covered in deranged racist scrawlings — including the N-word on the scope.

All but two of the 13 people shot were black — and the footage showed the gunman apologizing to one of the white people who came into his view.

It later emerged that Gendron had meticulously detailed his twisted race-hate views in a diary, which showed he was radicalized during the early days of the COVID-19 pandemic and had planned the attacks for months beforehand.

Within thousands of daily diary entries posted to his Discord server, which was taken down after the attack, Gendron allegedly detailed plans to hit the Tops Friendly Markets and kill as many black people as possible in a deranged pursuit to “save” the white race. 

He made the writings and his livestream public about a half-hour before the massacre but it’s unclear how many had accessed the materials or if anyone tried to alert law enforcement. 

In a 180-page “manifesto” detailing the plan, Gendron sought to continue the slaughter after the Tops attack but was stopped by law enforcement before he could continue.