Two teenage gunmen opened fire at the Islamic Center of San Diego on Monday, killing three men during the attack before the suspects died a few blocks away, San Diego Police Chief Scott Wahl said. Wahl said investigators are treating the shooting as a hate crime, although he said there was no specific threat made against the Islamic center ahead of the attack.

Wahl said authorities found evidence that the suspects engaged in “generalized hate rhetoric,” and he declined to provide additional details at that time. He said “the circumstances that led up to this” would be disclosed in the days ahead, as police continued to investigate what led the teenagers to carry out the attack.

Before the mosque shooting, officers were already searching for one of the teenagers. Wahl said the search began after the teenager’s mother called police, concerned her son was suicidal and had run away, and Wahl added that weapons were missing from the home and the mother’s vehicle was gone. He said the police pursuit took on “even more urgency” once investigators learned the suspect was dressed in camouflage and with an acquaintance, details that Wahl said did not fit what he described as a suicide scenario.

Police used technology including automated license plate readers and dispatched authorities to a mall near where the car had been tracked, Wahl said. Officers also alerted a school where, he said, at least one of the suspects had been a student. While investigators continued interviewing the mother about places the teens might be, reports of a shooting at the mosque came in, Wahl said.

Among those killed at the Islamic center was a security guard whom police believe “played a pivotal role” in keeping the attack from being “much worse,” Wahl said. Wahl later described the guard’s actions at a news conference as heroic, adding, “Undoubtedly he saved lives today.” A family friend identified the guard as Amin Abdullah, and Shaykh Uthman Ibn Farooq, who spoke with Abdullah’s son, said Abdullah wanted “to defend the innocent” and decided to become a security guard.

The Islamic center said it is the largest mosque in San Diego County and includes the Al Rashid School, which offers courses in Arabic language, Islamic studies and the Quran for students ages 5 and up, according to the center’s website. Wahl said police responded within four minutes of being called, and as officers arrived, gunshots were reported a few blocks away where a landscaper was shot but uninjured. Wahl said the shooters were found dead in a vehicle stopped in the middle of a road nearby.

Video footage showed children being escorted out of the mosque parking lot as police vehicles surrounded the building. Parents were directed to a nearby area to retrieve their children, and the mosque’s director, Imam Taha Hassane, said it was “extremely outrageous to target a place of worship.” He said, “All the places of worship in our beautiful city should always be protected,” and he added that the center focuses on interfaith relations and community building, including earlier Monday tours by a group of non-Muslims.

The Council on American-Islamic Relations’ San Diego chapter condemned the shooting. In a statement, CAIR-San Diego Executive Director Tazheen Nizam said, “No one should ever fear for their safety while attending prayers or studying at an elementary school,” and that the group was working to learn more about the incident while urging prayers for the community.

President Donald Trump called the shooting a “terrible situation,” according to the AP report.