The teenage gunmen who killed three members of a San Diego mosque met online and connected over hate-filled ideology, the Federal Bureau of Investigation said Tuesday.

Search warrants served at three homes associated with the two gunmen recovered dozens of weapons, including pistols, rifles, shotguns, ammunition, tactical gear and a crossbow, FBI San Diego Special Agent in Charge Mark Remily said.

The guns were not registered to the shooters and belonged to one of their parents, San Diego police Chief Scott Wahl said. Investigators are still working to determine how the teenagers obtained the weapons and have not yet determined if they will be recommending charges.

A manifesto was also recovered, which showed the teens “didn’t discriminate on who they hated. It covered a wide aspect of races and religions,” Remily said. Investigators believed the teenagers created their plan after they discovered they were both in the San Diego area.

The gunmen appear to have been radicalized online to believe that the members of the mosque “didn’t belong because of how they looked or where they worshiped,” Remily said. “They couldn’t be more wrong.”

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

The vehicle where the two teens were later found dead with self-inflicted gunshot wounds contained writings that described “various ideologies outlining religious and racial beliefs of how the world they envisioned should look,” Remily said.

Law enforcement officers were seen at two San Diego County homes believed to be associated with the gunmen — at a home in Clairemont where 17-year-old Cain Clark lived, and another in Chula Vista, which online records show may belong to the family of 18-year-old Caleb Vazquez.

San Diego police were at Clark’s family home hours before the 11:45 a.m. deadly shooting at the Islamic Center of San Diego after Clark’s mother called officers concerned about her son’s well-being. She believed he was suicidal and he was reported missing, according to SDPD Chief Scott Wahl.

Police learned the son was believed to be wearing camouflage and was with a friend, and a more urgent search began.

“She realized she was missing weapons, multiple weapons, her vehicle was missing; there are details that she was beginning to develop a bigger picture as to what she was dealing with, was conveying that to our folks and we were trying to put that together as quickly as we could,” Wahl said Monday.

After tracking the teenagers for hours, a 911 call sent law enforcement racing to the mosque in Clairemont, about 10 miles from downtown San Diego.

The home was surrounded by federal agents and local detectives for most of the day, but it wasn’t until about 10:45 p.m. that a rush of law enforcement agents in tactical gear swarmed the home and served a search warrant.

Neighbors told NBC San Diego that the 17-year-old lived at the home with his family. They said that they had known him his whole life, and that he had waved to them Monday morning.

“She’s a mother for crying out loud, I lost my son so I know what she’s going through,” the neighbor told NBC San Diego. “I’m just so sad our country is going through all of this.”

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 was a member of the wrestling team at Madison High School. Canning said Clark had no record of disciplinary issues in high school.

One witness saw police surrounding the second home on Paradise Trail in Chula Vista. An investigation stretched overnight, one neighbor told NBC San Diego. Other neighbors said the family was quiet but nice.

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.

Muslim American organizations noted that anti-Muslim rhetoric has been on the rise across the U.S.

The Islamic Center 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 its website.

The Associated Press contributed to this report.