VENTURA, Calif. — A 37-year-old Simi Valley man faces more than three decades to life in state prison after pleading guilty to second-degree murder in the brutal April 2024 stabbing death of his father, law enforcement and county prosecutors announced.
Ventura County District Attorney Erik Nasarenko confirmed that Gerardo Arroyo Almanza (DOB 04/23/89) entered guilty pleas to second-degree murder for the killing of his father, Alfredo Arroyo Sancen. Almanza also pled guilty to three felony counts of criminal threats targeting additional family members present during the deadly encounter.
In addition to the primary felony counts, Almanza admitted to a special enhancement allegation for the personal use of a deadly weapon and acknowledged prior strike allegations under California’s Three Strikes law.
Violent Onslaught During Family Welfare Check
According to court filings and detailed case documentation released by the Ventura County District Attorney’s Office, the fatal incident occurred on April 6, 2024, in a quiet residential neighborhood of Simi Valley.
Driven by concern for Almanza's mental health, several of his family members drove to his Simi Valley residence to check on his well-being. As family members gathered near their vehicles parked across the street from the home, Almanza suddenly ran out of the residence armed with a large kitchen knife and aggressively confronted them.
Prosecutors detailed that Almanza made explicit verbal threats to kill his family members before chasing his mother and father around a parked vehicle. Almanza eventually caught his father, pinned the elderly man to the ground, and stabbed him multiple times in the torso.
Nearby neighbors began gathering as the assault unfolded, prompting Almanza to flee the scene on foot. An EMT-trained neighbor rushed to the victim's side to administer emergency first aid until paramedical personnel arrived. Sancen was rushed by ambulance to Los Robles Regional Medical Center in Thousand Oaks, where he tragically succumbed to his injuries.
Simi Valley Police Department officers responded to the scene and located Almanza hiding inside a residential area approximately one block away from the crime scene, taking him into custody without further incident.
Competency Proceedings and Prosecution Statements
Following his initial arrest and formal charging in April 2024, criminal court proceedings were suspended after defense counsel raised concerns regarding Almanza's mental state. On March 6, 2025, a court-appointed mental health expert formally determined that Almanza was incompetent to stand trial.
Almanza was committed to a state health facility for psychiatric treatment and restoration. Seven months later, on October 6, 2025, medical evaluations deemed Almanza restored to competency, allowing the criminal prosecution to resume in Ventura County Superior Court.
The murder case was prosecuted by Senior Deputy District Attorney Theresa Pollara, a veteran prosecutor assigned to the District Attorney’s Office Major Crimes Unit. SDDA Pollara commended the resolution of the case and expressed hope for the grieving family:
"This guilty plea brings accountability for Gerardo Almanza’s brutal act of violence against his father and his threats of violence against other family members," Senior Deputy District Attorney Theresa Pollara stated in an official release. "Our hope for the family is that they are able to move forward in their healing."
Final Conviction Details and Upcoming State Prison Sentencing
Under the terms of his formal court plea, Almanza pled guilty to multiple felony charges under the California Penal Code:
- California Penal Code § 187(a): Murder in the Second Degree
- California Penal Code § 422 (Three Counts): Criminal Threats
- California Penal Code § 12022(b)(1): Special Allegation – Personal Use of a Deadly Weapon
- California Penal Code § 667(e)(2)(A): Strike Offense Enhancements
Almanza remains held without bail at the Ventura County Pre-Trial Detention Facility pending his formal sentencing hearing.
He is scheduled to be sentenced on September 11, 2026, at 9:00 a.m. in Department 12 of the Ventura County Superior Court. At the hearing, Almanza faces a mandatory prison term of 30 years to life, plus an additional consecutive term of nine years and four months in California state prison.