San Diego Mosque Shooting Marks a Deadly First in the United States

The attack on the Islamic Center of San Diego, in which two teenagers killed three people before taking their own lives, appears to be the first ideologically motivated lethal attack on a mosque in the United States this century. Although much remains unknown about the perpetrators at this time, investigators have recovered anti-Islamic writings and the words “hate speech” were scrawled on one of the firearms.

CSIS’s terrorism dataset records dozens of attacks and plots targeting U.S. mosques and Muslim community centers since 1994, but none had previously produced a fatality. The 2016 murder of Imam Maulana Akonjee and Thara Uddin, shot as they walked home from a Queens mosque, comes nearest—though the killings happened blocks from the building and were never officially established as ideologically motivated. Likewise, the 2024 killing of Imam Hassan Sharif outside his mosque in Newark was ruled nonideological by investigators.

Prior attacks on U.S. mosques in the CSIS dataset have largely been less lethal by design: arsons set against empty buildings overnight and incendiaries that damaged property without endangering worshippers. In April 2023, for instance, Jackie Rahm Little attempted to burn down a Minneapolis mosque on two consecutive nights. Both attempts failed, and no one was harmed. Where perpetrators did clearly intend to kill, attackers frequently failed to reach their targets, including law enforcement intervening before attacks could be executed. In 2022, Xavier Pelkey and two juvenile coconspirators—ISIS supporters who viewed Shia Muslims as apostates—were arrested while planning a mass shooting at a Chicago-area Shia mosque, where they intended to separate the adults from the children and kill all the adults before moving on to additional mosques and synagogues. Six years earlier, three members of a Kansas militia calling itself the Crusaders were arrested before they could carry out a plot to bomb an apartment complex housing Somali Muslim families and a mosque.

Whether the absence of fatalities until now reflects successful law enforcement monitoring and interdiction practices, target hardening, limited capability or intent of prior perpetrators, or some combination of these factors is difficult to determine from the incident data alone. What is clear is that the San Diego attack departed from that record in the dimension that matters most.

The San Diego attack lands amid a broader pattern of violence against religious institutions in the United States. Synagogues, churches, and mosques have all been targeted by terrorism at roughly comparable frequencies in the CSIS dataset, though attacks on synagogues and churches have repeatedly produced mass casualties: 11 victims were killed at the Tree of Life synagogue in Pittsburgh in 2018, 9 were killed at the Emanuel African Methodist Episcopal church in Charleston in 2015, and 4 were killed at a Latter-day Saints meetinghouse in Grand Blanc, Michigan in 2025. Until now, mosques in the United States had been the outlier—frequently targeted but never the site of a lethal terrorism incident.

That contrast also separates the United States from other countries, where attacks on mosques have at times been highly lethal. In 2019, Brenton Tarrant killed 51 Muslim worshippers at two mosques in Christchurch, New Zealand. In 2017, Alexandre Bissonnette killed 6 worshippers at the Islamic Cultural Centre of Quebec City. The ideological influence of those attacks, however, has long reached American soil. In March 2019, John T. Earnest set fire to a mosque in Escondido, California, roughly 30 miles north of the San Diego attack, leaving graffiti referencing the Christchurch attacks, which had occurred weeks earlier. The following month, Earnest entered a synagogue in Poway, roughly 20 miles north of San Diego, with an assault rifle and killed one worshipper, again citing Christchurch as inspiration in a manifesto posted online before the attack. Investigators have not publicly disclosed whether the San Diego attackers drew on similar inspiration.

The San Diego attack comes during a period of violence directed at religious and ethnic communities in the United States perceived to be tied to conflicts in the Middle East. In May 2025, Elias Rodriguez shot and killed two Israeli embassy staffers outside the Capital Jewish Museum in Washington, declaring, “I did it for Palestine, I did it for Gaza,” after his arrest. In June 2025, Mohamed Soliman firebombed a march for Israeli hostages in Boulder, killing 1 demonstrator and injuring 29. In March 2026, Ayman Ghazali drove a pickup truck into a Detroit-area synagogue and opened fire, in an attack the FBI described as inspired by Hezbollah and carried out a week after Ghazali lost family members in an Israeli airstrike on Lebanon. It is too early to know for certain what motivated the San Diego attackers and how their attack may or may not differ from those of others.

In the days ahead, several questions will sharpen what this attack means: whether the attackers were connected to extremist networks online or in person, whether they drew on specific ideologies, and whether their preparation extended beyond the two of them. What is already clear is that mosques and Muslim community centers now share the same lethal precedent that has long shaped the security posture of synagogues and churches in the United States. Faith leaders were in Washington lobbying for increased federal security funding for religious institutions when the San Diego attack occurred. That funding, and the broader question of how to harden religious sites without making them feel like fortresses, will be more urgent in the weeks ahead.

Riley McCabe is an associate fellow for the Warfare, Irregular Threats, and Terrorism Program at the Center for Strategic and International Studies in Washington, D.C.