The indictment this week of a 17-year-old North Carolina girl in connection with the deadly May attack on a San Diego mosque indicates a more aggressive approach to domestic extremism, according to one Southern California researcher.
Sarah Santiago is accused of helping two San Diego teens carry out their May 18 attack on the Islamic Center of San Diego, officials said at a North Carolina news conference Monday.
Santiago is charged with three counts of first-degree murder and one count of conspiracy. She's being charged as an adult in North Carolina.
Her attorney told The Associated Press she is innocent of the charges.
Peter Simi, a Chapman University professor who's studied political violence and extremism for three decades, said the charges mark an escalation from law enforcement when it comes to domestic violent extremism.
"You certainly have not really seen those kind of aggressive efforts traditionally with more domestic-type extremist groups," Simi told KPBS in an interview Tuesday. "I think ... these charges do represent ... an effort that certainly is more expansive than in the past."
Two alleged gunmen — 17 and 18-years-old — killed three men outside the Islamic Center. The pair killed themselves in a vehicle a few blocks away.
The pair also intended to attack a synagogue and Black students at a local public high school, according to the San Diego Police Department.
The attack and suicides were livestreamed to three people, authorities said Monday.
Santiago was allegedly one of them.
Forsyth County District Attorney Jim O'Neill said the girl knew of the planned attack ahead of time and agreed to record and distribute the shooters' video.
She also allegedly published their writings, authorities said.
O'Neil said the case is an example of how some online communities foster and amplify hate.
"There exists in our world an underground subculture," O'Neill said. "It's an echo chamber of intense hate against different cultures and religions. They listen to each other, they talk to each other on encoded platforms — it radicalizes one another to the point where they carry out these horrific crimes of violence and murder."
Simi said the path of radicalization online should be familiar — more than a decade ago some extremists were radicalized consuming propaganda from the Islamic State, or ISIS. Spree killing and far-right domestic extremism isn't very different, he said.
"What we're dealing with in many respects is a whole culture of a kind of martyrdom, a culture of violence that celebrates violence, that glamorizes violence (and) treats violent perpetrators as heroes," he added.
Young people now are more susceptible to extremist content and communities because they are joining social platforms at younger ages and in larger numbers, he said.
Algorithmic content feeds have also changed those platforms.
"It wasn't that long ago that for a child to seek out this kind of stuff, they would have had to make a bit of an effort," Simi said.
Today, extremist materials find them.
"These online spaces and algorithms are really kind of navigating the material to people in a way," Simi said. "So the materials are finding people as opposed to people finding the material. The likelihood of being exposed to it has increased substantially."
So who is vulnerable to the messaging?
Simi said kids who've experienced trauma or are socially isolated are especially at risk. They might not have a supportive community at school or at home, he said.
"They may not have healthy relationships or any relationships," Simi said. "In some cases they may be very isolated."
