Washington (CNN) Domestic terror suspect Christopher Hasson, who is accused of planning a terror attack on politicians and media figures, also allegedly searched the internet for the home addresses of two Supreme Court justices as well as the best gun to kill African-Americans, according to court documents filed Tuesday.

Hasson pleaded not guilty in federal court last month to to weapon and drug charges that prosecutors say were connected to a plot to murder Democratic and media figures. Prosecutors said he wanted to conduct a mass killing and described his white supremacist views in previous court documents.

The new documents reveal that Hasson conducted an internet search for "are Supreme Court justices protected" about two weeks before searching for the home addresses of the two unnamed justices.

Prosecutors also allege in the court filing that Hasson's "internet search history lays bare his views on race."

According to the court filing, Hasson searched for the "best" gun with which to kill African-Americans, "after which he visited various firearm sales websites."

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