Ventura Sheriff Deputies Arrest Two El Rio Men for Firearm Violations

Nature of Incident: Unlawful Firearms Investigation
Report Number: 25-95567
Location: Unincorporated area of Oxnard known as El Rio
Date & Time: 09/03/2025 @ 0700
Unit(s) Responsible: West County Special Enforcement Unit, Headquarters Patrol, Headquarters Investigations

Suspects:
Jacob Johnson, 23 of El Rio
Isidoro Fonseca Muniz, 49 of El Rio

During the month of August 2025, deputies assigned to the Ventura County Sheriff’s Office Headquarters Station initiated a firearms investigation after responding to a call for service in the unincorporated area of Oxnard, known as El Rio, regarding a potential domestic violence incident.

During the investigation, deputies assigned to the Headquarters Station partnered with detectives assigned to the West County Special Enforcement Unit.

Over the course of the next several weeks, detectives from the West County Special Enforcement Unit assumed the investigation and obtained a search warrant for a residence located in the 2900 block of Alvarado Street.

On September 3rd, 2025, detectives served the search warrant at the residence. During the service of the search warrant, detectives detained a resident, later identified as Jacob Johnson, as part of the firearms investigation.

During a search of the residence pursuant to the search warrant, detectives located two unregistered semi-automatic handguns along with various types of ammunition. Detectives arrested Johnson and another resident of the location, identified as Isidoro Fonseca Muniz, each for a violation of 27545 PC – Unlawful transfer of a firearm. Both Johnson and Muniz were booked at the Pre-Trial Detention Facility in Ventura, CA.

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