A 17-year-old North Carolina girl who recorded a livestream of a shooting that killed three people at a San Diego mosque\u00a0in May, and disseminated the attackers\u0027 white supremacist writings, has been charged with murder by aiding and abetting, a district attorney said Monday.The girl\u0027s name was not immediately released during a news conference announcing the charges. Forsyth County District Attorney Jim O\u0027Neill said at a news conference that she was arrested last week and indicted by a grand jury Monday, just before she was due to begin the school year."The thought of her going back to school or with the weekend approaching, holy days approaching, we didn\u0027t know what she was capable of," O\u0027Neill said.\u00a0He also explained that under North Carolina law, "a person who aids and abets another to commit a crime is guilty of that crime ... \u00a0just as if he or she had personally done all of the acts necessary to constitute the crime."The two shooters in the attack, identified by authorities as Cain Clark, 17, and Caleb Vazquez, 18, stormed the Islamic Center of San Diego on May 18 before being driven back outside by a security guard who exchanged gunfire with them as he initiated a lockdown, helping to protect 140 children who were inside.Police said the gunmen killed the guard, Amin Abdullah, and two other men, Mansour Kaziha and Nader Awad, before taking their own lives in a vehicle nearby.\u00a0They left behind rambling writings full of vitriol against a wide range of people.\u00a0The document, reviewed by CBS News, opens with an antisemitic diatribe, calls for a violent race war and references "accelerationism," one of the most violent forms of white supremacist ideology that advocates the destruction of society. They also pointed to the shooter who killed 51 people at two mosques in Christchurch, New Zealand, in 2019, as one of their models for the violence.The livestream was recorded using GoPro helmets worn by the gunmen, O\u0027Neill said."Their plan that day was to commit mass murders not only at the mosque but to follow up at a local Jewish temple and finally at a predominantly African American high school there in town," he said.Authorities had said the teens had stockpiled 30 guns and a crossbow, weapons taken from Clark\u0027s parents.The San Diego County DA\u0027s Office said in a statement Monday: "The investigation into the horrific murders of three innocent people targeting the Islamic Center of San Diego includes identifying anyone who has potential criminal liability. We are fully aware of the prosecution by the Forsyth County District Attorney\u0027s Office in North Carolina in connection with the San Diego murders and we are grateful for the efforts by DA Jim O\u0027Neill and his office."