New York Gov. Kathy Hochul, D., tasked social media companies with doing a better job monitoring speech on their platforms following the deadly mass shooting at a supermarket in Buffalo Saturday.

A gunman opened fire in a Tops Friendly Markets grocery store Saturday, killing 10 people and wounding three more, Buffalo police commissioner Joseph Gramaglia revealed in a press conference. Eleven of the victims are Black and two are White, according to authorities. The suspect, an 18-year-old White male named Payton Gendron, is being charged with first-degree murder and pleaded not guilty Saturday night. He is due back in court Thursday for a felony hearing.

The suspected shooter had published an approximately 180-page manifesto online before the shooting, in which he described himself as a White supremacist and detailed his fears that White people are being replaced by other races. He was likely planning the attack for months in advance, according to authorities.

Hochul argued that one of the first orders of business was for social media companies to more closely monitor the content on their platforms.