Candles with victims names are placed outside the Islamic Center of San Diego in the aftermath of a shooting on Wednesday, May 20, in San Diego. AP-Yonhap

In rambling writings full of vitriol against a wide range of people, the teenagers who attacked the Islamic Center of San Diego this week, killing three men and themselves, left little doubt about the models for their violence.

Chief among them: the shooter who killed 51 people at two mosques in Christchurch, New Zealand, in 2019.

Researchers who study extremism have long noted the resonance of the Christchurch attack among far-right assailants, attributing it to the extent of the violence, the document the killer posted concerning his views and actions, and — especially — his decision to livestream the massacre. Among those who apparently modeled attacks after Christchurch was a shooter who months later killed 22 people in a Texas Walmart.

“Part of what we’re seeing in violent extremist communities online is wanting to emulate the attacks that have had the most kills — which is a disgusting thing to say, but it's the reality,” said Katherine Keneally, director of threat analysis and prevention at the Institute for Strategic Dialogue, an anti-extremism organization. “There is this obsession and it’s just sort of gamifying of attacks.”