Joseph Czuba, 71, was indicted by a grand jury for the stabbing death of Wadea Al-Fayoume, and wounding his mother Hanaan Shahin on 14 October.
Police believe the mother and son were targeted with violence because of their Muslim faith.
Ms Shahin told law enforcement that Mr Czuba was upset over the Israel-Hamas war. On the day of the attack, he reportedly visited her apartment and knocked on her door. When she opened her door he began arguing with her about the situation in Israel and Gaza, and allegedly attacked Ms Shahin and Wadea after she asked Mr Czuba to "pray for peace."
She locked herself in her bathroom and called 911 after breaking away from her attacker, according to CBS News. While she was locked and injured in her bathroom, Mr Czuba allegedly proceeded to stab Wadea 26 times. The boy died from his wounds.
Ms Shahin is still recovering from her wounds and was unable to attend her son's funeral due to her injuries.
The indictment charging Mr Czuba said the murder displayed "exceptionally brutal or heinous behaviour."
Mr Czuba did not speak during the plea hearing and an attorney representing him said he is concerned that he will not be able to find an impartial jury for the case.
In addition to the local investigation, the Justice Department is also investigating whether or not Mr Czuba committed a federal hate crime.
Detectives speaking with Mr Czuba’s wife were told that he regularly listened to conservative talk radio and had become “very interested” in the war in Israel and Gaza.
Mr Czuba reportedly told his wife that they “were in danger” and feared that Ms Shahin would “call over her Palestinian friends or family to harm them.”