.gers who shot and killed three people in an attack on a California mosque were radicalised online where they first met and shared white supremacist views, according to authorities and writings they authored.

The pair “didn’t discriminate on who they hated”, Mark Remily, the lead FBI agent in San Diego, said Tuesday.

The writings, obtained by The Associated Press, include hateful rhetoric toward Jewish people, Muslims and Islam, as well as the LGBTQ+ community, black people, women, and both the political left and right.

Both express beliefs that white people are being eliminated, and one writes about mental health struggles and being rejected by women.

The suspects, ages 17 and 18, were found nearby in a vehicle after killing themselves.

Investigators also found guns, ammunition and a crossbow at two residences after Monday’s attack in San Diego and were trying to uncover whether the shooters had broader plans, Remily said.

Authorities praised the three men who died — including Amin Abdullah, a beloved security guard — for slowing the attackers at the Islamic Centre of San Diego and preventing them from reaching 140 school children just steps away.

Imam Taha Hassane said Abdullah engaged the suspects in a gun battle and called for a lockdown on his radio. He “sacrificed his life to stop them from getting inside the classrooms”.

The shooting was the latest in a string of attacks on houses of worship and comes amid rising threats and hate crimes targeting the Muslim and Jewish communities since the beginning of war in the Middle East, forcing increases in security.

Writings show broad hatred of shooters

Authorities have not officially released the names of the suspects, but the writings are authored by Cain Clark and Caleb Vazquez. Soon after the shooting investigators were seen searching the San Diego home of Clark’s parents.

Two senior law enforcement officials and a federal law enforcement official identified the pair as the shooters, NBC reports.

Authorities have said there was no specific threat against the Islamic centre, which is the largest mosque in San Diego, police said. In Cain’s writings, he calls for Muslims to be “exterminated”.

The document includes symbols long associated with white supremacists and Nazis.

The two referred to themselves as “Sons of Tarrant”, an apparent reference to the last name of the mass shooter who attacked mosques in Christchurch, New Zealand, in 2019, killing 51 people.

Muslim American organisations pointed out that anti-Muslim rhetoric has been on the rise across the US.

“Words have consequences,” said Mohamed Gula, interim CEO of advocacy group Emgage Action.

The two suspects met online before discovering they both lived in the San Diego area, the FBI said.

“In terms of how the radicalisation occurred, we’re still digging into that,” Remily said.

James Canning, a spokesman for San Diego Unified School District, said Clark had been attending school online since 2021 and was set to graduate next month.

In 2024, he participated as a member of the wrestling team at Madison High School. Canning said Clark had no record of disciplinary issues in high school.

Neighbours Marne and Ted Celaya said they last saw Clark a few hours before the shooting and that he waved as he got into a car alone and drove away.

They described the family as good neighbors and remembered when Cain was born, watching him and his older brother grow up.

“It’s unbelievable,” Marne Celaya said of the shooting. “He’s helped me bring in my groceries.”

The victims were pillars of the mosque

Police said the security guard opened fire when the shooters arrived at the Islamic Centre and tried to barge inside.

As the shooters made their way into the lobby, they wounded the guard who kept firing at them, forcing them back outside where the attackers fatally shot him, Police Chief Scott Wahl said.

The pair went back inside the school and searched through rooms that were emptied during the lockdown before they were drawn into the parking lot by the two others who were killed, Wahl said.

Mosque leaders identified the victims as Abdullah, Mansour Kaziha and Nader Awad.

Kaziha, known as Abu Ezz, “was everything” to the Islamic Centre, Hassane said. “He was the handyman. He was the cook. He was the caretaker,” Hassane said.

Abdullah had worked at the mosque for more than a decade.

“He wanted to defend the innocent so he decided to become a security guard,” said Shaykh Uthman Ibn Farooq, who spoke with Abdullah’s son.

Search began two hours before attack

Two hours before the attack police were racing to find the two teenagers.

The search began after the mother of one teen reported that her son was suicidal and had run away, Wahl said. Weapons and her vehicle were missing from the family’s home.

Police found the missing teen had dressed in camouflage — raising their alarms — and was with a friend. Officers used automated licence plate readers to track the car to a mall and went there.

The police chief said that while other officers were talking with the suspect’s mother who had called police, the first reports of the shooting came from blocks away at the mosque, which sits in a neighborhood with Middle Eastern restaurants and markets.

The centre includes the Al Rashid School, which offers courses in Arabic language, Islamic studies and the Quran for students ages five and up, according to its website.

As officers searched the mosque for the shooters, there were reports of people in a fleeing vehicle shooting at a landscaper who was not seriously hurt, Wahl said. Police then found the suspects dead.

Daniel McDonald said he was inside his house when he heard gunshots. He went outside to find the streets shut down, shattered glass on the pavement and a gardener who was shaken up. He said he saw police trying to revive one of the suspects.