SAN DIEGO — A fascination with mass killings, dressing like a fictional TV serial killer, telling a friend not to go to school the next day — all are part of the troubling behavior a Chula Vista school official cited after calling police last year about a then-student who later became one of two teenage gunmen suspected of killing three men at San Diego’s largest mosque, court documents indicate.

Well more than a year before the May 18 attack, Caleb Vazquez’s behavior had so concerned officials that he was placed on a 72-hour involuntary hold for a mental health evaluation, feared to be a danger to himself or others, court documents indicate. He was then 17 years old and a student at High Tech High in Chula Vista.

Vazquez, 18, and friend Cain Clark, 17, fatally shot three men outside the Islamic Center of San Diego in the late-morning attack before driving several blocks away and killing themselves, San Diego police said. Authorities said the teens met online, where they were radicalized by hate. The FBI recovered a manifesto, and the attack is being investigated as a hate crime.

Vazquez had drawn attention well before. In January 2025, court documents show, Chula Vista police sought a court order to strip the high school senior’s access to guns for up to five years, saying the teen’s behavior was “very concerning.”

“He has become increasingly obsessed with mass shooters, school shootings, neo-Nazi affiliations and Hitler,” an officer wrote in a petition seeking an emergency order.

Police sought a gun violence restraining order, which must be approved by a judge and is intended for crisis intervention. Such civil orders require a person to surrender or sell their firearms and bar them from having guns or ammunition. They are often obtained quickly after an incident and start out as temporary orders, followed by a court hearing for a judge to consider extending them.

It was one of two emergency court orders Chula Vista police sought in early 2025 to strip the teen’s access to guns. Police also sought a separate order to take guns from his father.

Because the subject of the January 2025 court order was a minor, his name and identifying information were redacted from the filings, and the case was filed under the initials C.V. However, the name “Caleb” appears in the petition to secure an emergency court order. Additionally, other information in the filings aligns with information in court filings from the case served on his father not long after.

According to a declaration filed by a Chula Vista police officer, the teenager alarmed a friend on Jan. 23, 2025, warning him not to attend school the next day. The student notified a school official, who in turn contacted police. About 10:30 p.m., Chula Vista police were on the teen’s doorstep and aware that his father had 12 firearms registered. The father — who later filed a declaration that his weapons were in a safe — did not allow police to verify the storage, nor did he allow police to speak to his son alone.

With his parents present, the teen told police he was bullied for being quiet and shy, for the way he dressed and for his conservative world views, according to the declaration.

Police spoke again to the school’s vice principal, and he told police he already had concerns about the teenager, who had reportedly displayed troubling behaviors, according to the declaration, including allusions to school shootings and violence. According to the declaration, the school had “conducted multiple threat assessments and wellness checks” on the teen.

After a breakup, the teen was spotted punching a tree and behaving irrationally, the declaration states. The school official shared examples of other concerning behavior, according to the declaration. In mid- to late-2024, the school administrator told police, the teen showed up at school dressed like “Dexter,” a fictional TV serial killer. The teen had also reportedly made comments about wanting to experience “a day of retribution,” referencing the deadly 2014 Isla Vista shooting spree near Santa Barbara, and expressed fascination with other mass attacks, according to the declaration.

The teenager’s “apparent admiration for these figures and incidents suggests a fixation on violence and extremist ideologies, which raises concern about his mindset, potential for radicalization, and the possibility of harm to himself or others,” the officer wrote in the petition. “This behavior further signals a need for intervention to address these alarming tendencies before they escalate.”

The day after police were at his home, the teen spoke to school resource officers and a psychiatric emergency response team clinician, telling officers he’d had a hard time since his breakup and “has been becoming increasingly infatuated with mass shootings and World War II,” the declaration reads. The teen told the clinician he’d dressed up as the suspect accused of gunning down a healthcare executive in Manhattan in 2024, according to the declaration. The teen also said that the infatuation with mass shooters looked bad, but it was nothing more than infatuation, according to the declaration.

After police spoke to the teen and his family, but before police sought the emergency court order to confiscate guns, the father and his wife voluntarily stored 26 weapons — pistols, rifles and shotguns — with a licensed gun dealer, according to filings in the father’s case. In a declaration in the case against the father, the father wrote that he and his wife also had “significantly increased” monitoring of the teen.

Police secured the emergency orders in late January. In mid-February, the family and police agreed to dismiss the matter against the father, and the emergency order to take the guns from the father was dissolved.

A month later, in March, a superior court judge agreed to rescind the protective order against the son. The court minutes do not indicate why.

Police have not said where the guns used in the mosque shooting came from. The mother of the other suspect, Clark, reported to police the morning of the shooting that guns had gone missing from her home.

Last week, Vazquez’s parents issued a lengthy statement mourning the victims and condemning their son’s actions as those of “an immensely lost, troubled, and misguided soul.”

“We are completely heartbroken and devastated by what has happened,” the statement reads. “We condemn these hateful and violent actions entirely.”

High Tech High officials issued a statement that one of the shooters was a graduate of the school. High Tech also condemned the attack.

“We recognize that members of our own community — particularly our Muslim students, staff, and families — may be experiencing deep pain, anxiety, or retraumatization right now,” school officials said in a letter issued last week. “Please know that we see you, we stand with you, and we join the larger San Diego educational community in firmly condemning hate in all its forms.”

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(Union-Tribune staff writer Jemma Stephenson contributed to this report.)

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