MENDOCINO CO., 7/24/26 — Sheriff’s deputies serving a search warrant at an illegal cannabis grow this week near Covelo arrested one armed man and found nearly 10,000 marijuana plants and the banned pesticide carbofuran, while a second armed man fled with what the sheriff described as a modified assault rifle, Mendocino County Sheriff Matt Kendall said.
Deputies encountered the two men as they served the warrant, Kendall said in a statement posted Thursday to the sheriff’s office Facebook page. One ran and eluded capture. The second, also armed, was taken into custody without injury although deputies “had to work hard to convince him to give up peacefully,” the sheriff wrote.
Kendall did not name the man who was arrested. However, jail intake records show that Mario Caballero, 53, of Covelo, was booked into the Mendocino County Jail at 4:11 p.m. Thursday on charges matching that account: felony cultivation of marijuana and illegal diversion of water, felony possession of an assault weapon, a felony count of being armed with a firearm in the commission of a felony, and a misdemeanor count of possession of marijuana for sale. The records list the sheriff’s office as the arresting agency and give an offense date of Thursday. Caballero remained in custody Friday; the booking record lists no bail.
The raid was one of several warrant services deputies carried out across the county this week. Sheriff’s media logs show deputies serving warrants on Hulls Valley Road near Covelo on Wednesday and Thursday mornings. Kendall described a broader pattern of “serious crime with violence and continued environmental degradation” at illegal grow sites. “Sadly these things we are seeing are becoming the rule, not the exception,” he wrote.
The site held nearly 10,000 marijuana plants, along with firearms, water diversions and illegal pesticides including carbofuran, the sheriff said. The sheriff’s office said it is working with environmental scientists to assess the damage and would release a fuller account “as soon as we are able.”
Carbofuran is a highly toxic carbamate insecticide that the U.S. Environmental Protection Agency effectively banned in 2009, when it revoked the residue tolerances that had allowed the chemical on food crops. A single granule can kill a bird, and the pesticide has been used to poison wildlife in the United States, Canada and Britain.
The chemical has turned up repeatedly at illegal cannabis grows in California. Mourad Gabriel, an ecologist with the Integral Ecology Research Center, found carbofuran at 72% of the grow sites his team sampled in 2017, up from 15% in 2012. The containers are typically labeled in Spanish, Gabriel has said, and the chemical is smuggled in from Mexico.