Stolen firearm case turns into sweeping weapons investigation

What began as a standard response to a residential burglary in Thousand Oaks has evolved into a sweeping, months-long firearms investigation. According to an Aug. 3 statement issued by the Ventura County Sheriff’s Office (VCSO), the complex case has resulted in three arrests and the seizure of more than 20 firearms, narcotics, thousands of rounds of ammunition, and dozens of high-capacity magazines across multiple local residences.

The Thousand Oaks Acorn first detailed the intricate web of suspects and illicit weapons, illustrating how a single neighborhood crime can unearth broader underground networks operating within the Conejo Valley.

From Neighborhood Burglary to Multi-Agency Investigation

The chain of events initiated in May 2026 when Thousand Oaks patrol deputies responded to a residential burglary in the 2900 block of Teresa Drive. Investigators quickly determined that a local resident, Frank Holzer, had stolen firearms from 49-year-old Tasha Dunning.

Deputies subsequently located Holzer, recovering several of the allegedly stolen weapons. Among the recovered cache was an assault weapon and a privately made firearm, often referred to as a "ghost gun." Following Holzer's arrest by the Thousand Oaks Police Department, the case was transferred to the VCSO’s Gun Violence Reduction Program. This specialized unit expanded the scope of the inquiry, shifting the focus from a standalone property crime to a broader probe into illegal firearms activity in the region.

Uncovering a Cache on Teresa Drive

Investigators soon turned their attention back to the original victim in the case. On May 28, with assistance from the Sheriff’s Special Crimes Unit, detectives served a search warrant at Dunning’s residence. The search yielded a massive cache of lethal materials. According to the VCSO, detectives recovered 14 firearms, several thousand rounds of ammunition, approximately 50 high-capacity magazines, and a quantity of ecstasy (MDMA).

Officials noted that many of the firearms found in the home were unregistered. Furthermore, at least one weapon recovered during the search met the statutory definition of an assault weapon under California law. Dunning was arrested on multiple firearms and narcotics violations, and her case was submitted to the Ventura County District Attorney’s Office for filing consideration.

Expanded Search Leads to Newbury Park

The execution of the warrant on Teresa Drive did not conclude the investigation. During the search of Dunning's home, detectives uncovered evidence directly tied to a tenant residing at the property. Inside the tenant's room, authorities found an unregistered Glock handgun, ammunition, cocaine, and additional high-capacity magazines.

The evidence led investigators to identify the tenant as 30-year-old Kastan Jones, who was arrested on June 12. Prosecutors subsequently filed weapons and narcotics charges against him, along with a charge for driving with a suspended license.

Acting on leads developed during Jones' arrest, detectives identified 30-year-old Randall Cota of Newbury Park as a close associate. The VCSO developed intelligence linking Cota to ongoing unlawful firearm activity. On July 15, members of the Gun Violence Reduction Program and the Thousand Oaks Directed Enforcement Unit served a search warrant at Cota’s Newbury Park residence.

The search of the property resulted in the recovery of nine firearms, high-capacity magazines, and several thousand rounds of ammunition. Detectives noted that one of these firearms also met the legal definition of an assault weapon, and two pistols were unregistered. Cota was booked into the East Valley Jail on suspicion of possessing an assault weapon, the unlawful transfer of a firearm, possession of a large-capacity magazine, and being an addict in possession of a firearm. His case was likewise forwarded to the District Attorney’s Office.

The Reality of Gun Violence Reduction on the Central Coast

The trajectory of this investigation highlights the increasingly complex nature of firearms enforcement on the Central Coast. The VCSO’s Gun Violence Reduction Program, which spearheaded the expansion of this case, operates specifically to investigate the illegal possession, manufacturing, and trafficking of firearms. Cases like this demonstrate how deeply intertwined illegal weapons can be with other criminal activity, including narcotics distribution and residential burglary.

For Thousand Oaks residents, the operation serves as a stark reminder of the illicit activity that can occasionally lurk behind closed doors in otherwise quiet suburban neighborhoods. The presence of privately made firearms and unregistered assault weapons poses specific challenges for local law enforcement, as these weapons lack serial numbers and are difficult to trace.

As the legal process moves forward, the community will be watching how the Ventura County District Attorney’s Office proceeds with the charges against Dunning and Cota. Meanwhile, the VCSO continues to encourage residents to report suspicious activity, emphasizing that community vigilance often serves as the critical first step in dismantling broader criminal operations.