A North Carolina teenager has been indicted on murder charges for allegedly helping orchestrate the livestreaming and promotion of a deadly mass shooting at a San Diego mosque — an attack she watched unfold on her phone from more than 2,300 miles away.

Forsyth County District Attorney Jim O'Neill announced Monday that a grand jury indicted Sarah Lindsay Santiago, 17, of Winston-Salem, on three counts of first-degree murder and one count of conspiracy to commit first-degree murder. She is being charged as an adult and is being held without bond, according to the Washington Post. Her next court hearing is set for Sept. 21.

Prosecutors say Santiago agreed in advance with two San Diego teenagers, Cain Clark, 17, and Caleb Vazquez, 18, that she would record and distribute a livestream of their planned attack and later publish a manifesto the pair had written. She is also accused of buying a patch bearing a white-supremacist "Black Sun" symbol and mailing it to one of the gunmen to wear during the shooting.

On May 18, Clark and Vazquez stormed the Islamic Center of San Diego and killed three men — security guard Amin Abdullah, 51, along with Mansour Kaziha and Nadir Awad — before taking their own lives in a vehicle nearby, according to KPBS. Abdullah, who had worked security at the mosque for more than a decade, exchanged gunfire with the attackers outside the building and radioed a lockdown warning before he was killed — actions officials have credited with saving lives inside. Investigators have said the attackers, motivated by white-supremacist ideology, had also plotted further attacks on a synagogue and Black students at a local high school.

Distance No Shield, Prosecutors Say

O'Neill's office argues North Carolina law does not require a defendant to be physically present to face the same charges as the shooters themselves. "A person may be guilty of a crime, although he or she personally does not do any of the acts to constitute the crime," O'Neill said in announcing the indictment, according to Times of San Diego.

"Physical distance from an attack does not place someone beyond accountability."

That line came from FBI Special Agent Mark Remily, who said the case shows investigators will pursue anyone connected to an attack's planning, no matter where they were sitting when it happened.

Santiago's attorney, Alan Doorasamy Sr., pushed back on the charges, telling reporters his client "is innocent of all these charges," per NBC News. He has not detailed a defense strategy ahead of the September hearing.

The case adds a disturbing new dimension to an attack that already shocked the country: evidence that an accomplice hundreds of miles away allegedly helped plan the shooting's amplification as carefully as the gunmen planned the killing itself. Investigators have not said how Santiago and the two shooters connected online, but the indictment describes coordination well before the May attack, including her alleged purchase and mailing of the extremist patch. It remains unclear whether additional arrests are possible as the FBI's investigation into the broader network continues.