San Diego Islamic Center attack investigated as hate crime

Two teenagers attacked the Islamic Center in San Diego on Monday, killing three people before turning their guns on themselves, authorities said. Officials are investigating the incident as a hate crime and working to determine a motive. The gunmen left behind a 75-page manifesto that contained anti-Islam ideology, antisemitism and calls for violence.

Authorities also identified social media accounts believed to belong to one of the attackers that included content promoting white nationalism, neo-Nazi terrorism and school shootings.

Online exposure and radicalization Teens access the internet earlier and more frequently than previous generations. Psychologists and psychiatrists say young people in their formative years can encounter extremist material and, in some cases, connect with extremist groups while seeking social belonging.

Anne Speckhard, director of the International Center for the Study of Violent Extremism, has studied terrorists for 20 years. She said historical assumptions that homegrown terrorists could not be recruited online no longer hold because the internet is so personal.

Morteza Dehghani, professor of psychology and computer science at USC, said social media algorithms can simulate the tight-knit environment once provided by local groups at a much larger scale. He added that experimental data show identity fusion with an online group increases willingness to engage in radical behavior.

Speckhard said some young people turn to the internet when they do not find belonging or significance in daily life. Algorithms can then feed more of the same content, she said. Dehghani advised parents to notice sudden shifts in a child's identity, morality or attachment to an online group.

He said use of purity-related language that frames other groups as corrupt or disgusting is a warning sign. Parents can break echo chambers by discussing online routines with their children and exposing them to a range of viewpoints on moralized topics such as immigration, Dehghani said.