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A suspect was arrested and charged with murder in the stabbing death of a 15-year-old boy in El Monte.
The Los Angeles County Sheriff’s Department identified the suspect as Jonathan Castelan, 18, of South El Monte.
The incident occurred on July 10 as deputies were called to the 9700 block of Fern Street near Potrero Elementary School around 1 p.m. Investigators said that during an altercation, three people were stabbed.
Aziel Zacapala, 15, along with two unidentified friends, were hospitalized with stab wounds. Zacapala later died from his injuries. The suspect fled the scene before deputies arrived.
The victim, Aziel Zacapala, 15, was stabbed to death in El Monte on July 10, 2026. (El Monte Union High School District) Aziel Zacapala, 15, was stabbed to death in El Monte on July 10, 2026. (GoFundMe) Aziel Zacapala, 15, was stabbed to death in El Monte on July 10, 2026. (El Monte Union High School District)
After nearly two weeks of investigating, on July 20, detectives arrested Castelan in connection with the case. On July 22, he was charged with one count of murder, one count of attempted murder and one count of assault with a deadly weapon.
The victim, Zacapala, was a football player at Rosemead High School who was about to start his sophomore year.
Known as “AZ” by his friends and classmates, his family said the teen had a “golden heart” who brought joy and laughter to those around him.
“He was just a really good kid overall,” his mother, Maria Aguilar, told the San Gabriel Valley Tribune. “He had a lot of dreams.”
Zacapala’s family said he aspired to be a professional football player and was excited to start his sophomore year playing on the varsity football team.
A GoFundMe page for Zacapala’s family described the teen as a “beloved nephew, friend, son and high school football player whose life was tragically cut short. His dedication to his sport and his positive spirit inspired everyone around him, and his absence leaves a deep void in our family and community.”
A homicide investigation is underway after a boy was stabbed to death near an elementary school in El Monte on July 10, 2026. (KTLA) A homicide investigation is underway after a boy was stabbed to death near an elementary school in El Monte on July 10, 2026. (KTLA) A homicide investigation is underway after a boy was stabbed to death near an elementary school in El Monte on July 10, 2026. (KTLA) A homicide investigation is underway after a boy was stabbed to death near an elementary school in El Monte on July 10, 2026. (KTLA)
Investigators have not released details on what prompted the deadly stabbing or how the suspect and victims were known to each other.
In a statement, the El Monte Union High School District said, “With heavy hearts, El Monte Union mourns the passing of Rosemead High School rising sophomore Aziel Zacapala. Our deepest condolences are with Aziel’s family, friends, classmates, teammates, and the entire Rosemead High School community as we navigate this heartbreaking loss.”
Anyone with information about the incident is asked to call the LASD’s Homicide Bureau at 323-890-5500.
Anonymous tips can be provided to L.A. Regional Crime Stoppers at 1-800-222-8477 or online at lacrimestoppers.org.
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