DA: Esparto fireworks site had 1 million pounds of explosives when blast killed 7
Yolo County prosecutors on Friday unveiled sweeping grand jury indictments charging seven men and one woman in connection with a July 1, 2025, warehouse explosion near Esparto that killed seven people and was tied to an alleged “massive” illegal fireworks importation, manufacturing and sales operation.
Five of the men face second-degree murder charges, accusing them of being criminally responsible for the deaths of workers killed when fireworks ignited at a rural compound at County Roads 23 and 86A just days before the Fourth of July.
At a news conference Friday in Woodland following a monthslong investigation, prosecutors described the site as a “hub of illegal fireworks,” alleging the group repurposed and sold explosives marketed across California as consumer-grade fireworks under the guise of a legal display fireworks business well known across Northern California.
The indictment — handed up 276 days after the blast and unsealed the day all eight were arrested — alleges what prosecutors called “a decadelong conspiracy ... to construct a massive and illegal fireworks and explosives operation” in Yolo County.
Yolo County District Attorney Jeff Reisig called the explosion a “terrible, terrible event for the seven people that died and the community,” and said investigators were “committed from day one to seeking the truth and finding out what happened” for the loved ones of the victims, whose names were read aloud during the 25-minute briefing.
The victims of the blast in Esparto are Jesús Ramos, 18; Jhony Ramos, 22; Joel “Junior” Melendez, 28; Carlos Rodriguez-Mora, 43; Angel Mathew Voller, 18; Christopher Bocog, 45; and Neil Li, 41.
More than 1 million pounds of fireworks were on site and near the Machados’ home when the inferno began, prosecutors said, who told reporters that as many as 11 million pounds of pyrotechnics had been imported and moved through Esparto over the course of a decade.
8 total suspects face felony charges
Samuel Elmo Machado, 45, and his wife, Tammy Kiku Machado, 46 — both employees of the Yolo County Sheriff’s Office and owners of the property where Devastating Pyrotechnics and BlackStar Fireworks operated — were among those facing felony charges.
“This is not a case just about fireworks,” Deputy District Attorney Clara Nabity said. “They are explosives ... designed and packaged for consumer sales under private labels.”
Machado also faces four felony counts of possession of an assault weapon after three semi-automatic rifles and one semi-automatic pistol were found on his property after the July 2025 explosion.
Both Machados — Tammy, a legal secretary, and Sam, a lieutenant — submitted resignation letters effective March 17 after being on paid administrative leave since the blast, Sheriff Tom Lopez said at a news conference at his office. Each had worked for the Yolo County Sheriff’s Office for nearly 25 years. Sam Machado previously worked at the Madison Fire Protection District, just east of Esparto, where Lopez served as chief before his election as sheriff in 2018, according to previous Bee reporting.
Both had been placed on administrative leave on July 10 and remained in that status until their resignations, Lopez said.
Reiko Matsumura, Tammy Machado’s sister and another longtime Yolo County sheriff’s deputy, retired in September, about two months after the explosion tied to the family’s Esparto-area properties. Matsumura, who served nearly two decades with the agency, never returned to duty after the blast, though officials said she was not placed on administrative leave. The sisters split the property they inherited from their father, Jerry Matsumura, after his 2015 death.
Matsumura’s similarly sized parcel on County Road 86A next door to the Machados also housed fireworks in several containers licensed by the Bureau of Alcohol, Tobacco, Firearms and Explosives that were not part of the explosion, The Bee previously reported. She was not indicted by the grand jury.
Machado tenants and the operators of the fireworks companies, Kenneth Kin Chee, 47, of Devastating Pyrotechnics and Craig Allen Cutright, 61, of BlackStar, were among those taken into custody Thursday.
Also arrested was Douglas Michael Tollefsen, 55, an associate of Chee’s who allegedly helped import millions of pounds of explosives into the country from overseas before they were moved to Esparto to be repackaged and sold as consumer fireworks. It was the first time Tollefsen, a resident of Rio Linda, was publicly named in connection with Devastating’s operations.
Tollefson in March 2016 posted to Facebook a photo of a road sign reading “Transporting illegal fireworks prohibited,” which he said in a comment he took on the California side of the state’s border with Nevada near Pahrump. On the eve of his arrest, Tollefson posted a video of a vegetation fire in a field, captioned “Fire season... #fire #burn #flame.”
5 charged with murder with workers’ death
Machado, Chee, Tollefsen and two other men — Jack Y. Lee, 65, Devastating’s operations manager and the registered owner of the San Francisco home used as the business’ address; and Gary Y. Chan Jr., 43, who held the ATF license for the fireworks — face second-degree murder charges, Reisig said, flanked by a team of prosecutors and investigators.
“We really did seek to leave no stone unturned,” Reisig said.
The five, as well as Cutright and Ronald Botelho III, 30, were expected to be charged in Yolo Superior Court in the coming days with conspiracy to commit crimes, weapons violations and tax fraud in addition to charges of handling and possessing illegal fireworks.
All eight suspects were arrested Thursday. Five were booked into Yolo County detention facilities, where they remain. Chee, who operated Devastating for years without holding federal fireworks permits but held a state license, was arrested while on a “pre-planned vacation” at Disney World near Orlando, Florida, according to law enforcement officials and Chee’s lawyer.
Gary Chan Jr. was arrested in Santa Clara County. Botelho was already in custody in Crescent City following a December arrest involving fireworks tied to Devastating and was re-arrested on the new charges.
All seven men remain in custody and are being held without bail. Samuel Machado was being held in neighboring Sutter County, Chan remained in Santa Clara custody, and it was unclear when Chee would be extradited from Florida custody.
The five in custody in Yolo County will be arraigned Monday afternoon in a Woodland court, records show.
Child endangerment, animal cruelty charges
Tammy Machado was the only defendant not in custody after posting bond Thursday.
She faces child and animal cruelty endangerment charges arising from the storage of fireworks and materials used to make destructive devices near their home, according to prosecutors.
Prosecutors said the charges stem in part from “a substantial volume of explosives ... stored adjacent to a family pool” and near the Machado residence, according to Nabity.
Sprawling 9-month criminal investigation
Prosecutors said the operation blurred the line between legal display fireworks and illegal products allegedly manufactured and sold across the state. Officials from the DA’s Office remained tight-lipped about how sprawling the operation was, noting that the investigation was continuing and more would come out once the suspects are on trial.
“What I can say is that there’s a difference between a display business and sort of the illegal street sales of private label explosives,” Nabity said. “And so the indictment is focused on the alleged conspiracy of importing and selling on the street illegal explosives, and the display business is not really the focus of our criminal investigation.”
Nabity added that in 2015 the property had about 13 storage containers of pyrotechnics and by 2025 there were more than 50, in addition to the 5,000-square-foot warehouse, one of two in the compound.
Some of the fireworks imported were brands such as “Bad Dad” and “Double OG” for BlackStar Fireworks.
The Yolo County District Attorney’s Office has led the nine-month investigation with support from the ATF and from the California Department of Forestry and Fire Protection’s Office of the State Fire Marshal.
Cal Fire concluded its investigation into the cause of the explosion in February. A Cal-OSHA investigation levied fines against Devastating Pyrotechnics for workplace safety violations in December.
The Yolo County Board of Supervisors and Reisig asked California Attorney General Rob Bonta to spearhead the investigation due to the involvement of county employees, but Bonta’s office said they saw no conflict barring Reisig’s office from investigating and denied the request in August.
Reisig’s office committed unprecedented resources to the investigation, drawing on a recently retired deputy district attorney to support a team of prosecutors and five investigators. From the outset, his office has seen the seven deaths caused by the explosion as homicides, so they’ve approached the investigation with the rigor such cases demand, The Bee previously reported.
Reisig said Friday that the case represents the largest investigation undertaken during his tenure, calling it “massive” and noting it required coordination with federal, state and local agencies. He also noted the investigation has taken his team “across our national borders,” though he did not elaborate.
Cash-strapped Yolo County spent more than $1.7 million in the months after the explosion, most of which went toward Reisig’s investigation. The District Attorney’s Office requested more than $900,000 in added funding to hire the five investigators assigned to the investigation.
Authorities served dozens of search warrants, including one at the home of Esparto Fire Protection District Chief Curtis Lawrence. The investigation led Yolo County investigators to an East LA neighborhood, where they discovered a cache of illegal fireworks stashed in the home of Luis Acosta. It then led prosecutors to Del Norte County, where they arrested Botelho and confiscated more illegal fireworks.
Reisig’s office requested that the State Compensation Insurance Fund investigate Devastating Pyrotechnics for payroll fraud. That investigation uncovered records revealing that the company paid most of its employees in cash and underreported its payroll.
The Bee’s Michael McGough, Graham Womack and Daniel Hunt contributed to this story.
This story was originally published April 10, 2026 at 12:50 PM with the headline "DA: Esparto fireworks site had 1 million pounds of explosives when blast killed 7."
