LOS ANGELES, CA – A 27-year-old Ontario man was arrested in connection with an investigation into a pyrotechnic explosion in South Los Angeles that killed a 17-year-old last year, according to the Los Angeles Police Department.
Giovani Diaz was taken into custody on September 30 after investigators served search warrants at a storage facility in Rancho Cucamonga and a residence in the 900 block of North Duesenberg Drive in Ontario, authorities said.
Diaz was booked on suspicion of possession of a destructive device, and his bail was set at $500,000. Investigators have also presented additional potential charges to the Los Angeles County District Attorney’s Office, including allegations involving child endangerment and narcotics offenses.
The arrest stems from an investigation that began on December 3, 2025, when officers from the LAPD’s 77th Division responded at about 9:26 p.m. to reports of a male on fire in the 400 block of West 84th Street in South Los Angeles.
According to the LAPD, investigators determined that an unidentified person had been manipulating pyrotechnic materials when the materials exploded, causing serious injuries.
Los Angeles Fire Department personnel transported the injured person to a local hospital. The victim was later identified as a 17-year-old juvenile and died from injuries sustained in the explosion.
The investigation continued after the blast, with the LAPD Bomb Squad, Hazardous Materials Unit and Major Crimes Division detectives responding to the scene. Officers seized a large quantity of illegal pyrotechnic devices and moved the remaining explosive materials to a secure storage location.
Investigation expanded beyond the original explosion
As detectives continued working on the case, investigators identified several groups they believe were involved in illegal pyrotechnic activity and the sale of related components through social media, according to police.
The September 30 search warrants were part of that broader investigation. Authorities said the searches resulted in the recovery of multiple explosive devices and components, as well as currency, narcotics, drug paraphernalia and other evidence.
Police have not publicly established whether the materials recovered from the Ontario residence or the Rancho Cucamonga storage facility were directly responsible for the December 2025 explosion.
Authorities also have not disclosed the nature of any relationship between Diaz and the teenager who died.
The distinction is important because the arrest currently announced by police concerns possession of a destructive device. The investigation into the circumstances surrounding the teenager’s death remains ongoing, and the available information does not establish that Diaz has been charged with causing the fatal explosion.
Illegal pyrotechnics remain a public safety concern
The case also highlights the risks authorities associate with unauthorized fireworks and pyrotechnic devices in residential areas.
The Los Angeles County Fire Department says fireworks can cause serious burns, injuries and fires and notes that, in unincorporated areas of Los Angeles County, all forms of fireworks are prohibited without the required permits.
California regulations also restrict the possession, storage, sale and handling of dangerous fireworks and other pyrotechnic materials. The California Health and Safety Code establishes permitting requirements for dangerous fireworks, while California law separately regulates destructive devices and explosives.
For investigators, the December 2025 explosion was not treated simply as an isolated accident. The LAPD’s original investigation focused both on the circumstances that led to the teenager’s injuries and on determining the source of the illegal pyrotechnic materials found at the residence.
Police said there are no ongoing public safety concerns associated with the original scene.
Investigation remains active
The LAPD said detectives are continuing to investigate the explosion and the alleged illegal pyrotechnic activity connected to the case.
Anyone with information is asked to contact Major Crimes Division Detective Allen at 213-486-7260. During non-business hours or weekends, information can be provided through 1-877-LAPD-24-7.
Anonymous tips can also be submitted through L.A. Regional Crime Stoppers.
Diaz’s arrest and the allegations described by police are not a determination of guilt. Any additional criminal charges will depend on the continuing investigation and prosecutorial review.
