Man Sentenced to Prison for Killing His Father

A Simi Valley man will spend decades to life in state prison for the 2024 knife killing of his father, a case that prosecutors say began as a family wellness check and ended in a fatal attack witnessed by neighbors and relatives. The sentencing, announced by Ventura County District Attorney Erik Nasarenko, closes a legal process that stretched more than two years and included a lengthy detour over the defendant's mental competency to stand trial, according to the Vida Newspaper.

Gerardo Arroyo Almanza, 37, was sentenced to 39 years and 4 months to life in state prison for the murder of his father, Alfredo Arroyo Sancen. Almanza previously pled guilty on August 3, 2026, to second-degree murder and three counts of criminal threats against additional family members. He also admitted to a prior strike offense and a special allegation for the use of a weapon, the Vida Newspaper reported.

For residents across Ventura County — including here in Oxnard, the county's largest city — the case is a stark reminder of how domestic violence and family crises are handled within the county's courts, and how the criminal justice system navigates questions of mental illness when defendants face the most serious of charges.

What Happened on April 6, 2024

According to the account provided by the District Attorney's Office and reported by Vida Newspaper, the violence unfolded on April 6, 2024, when several of Almanza's family members drove to his residence in Simi Valley to check on his well-being.

While the family members were near their vehicles, parked across the street from the home, Almanza ran out of the house and confronted them with a knife, threatening to kill them, the report stated. Almanza then chased his mother and father around a parked car. After catching his father and pinning him to the ground, Almanza stabbed him several times.

As neighbors began to gather, Almanza fled the area. An EMT-trained neighbor provided first aid to Sancen before he was transported by emergency medical services to a hospital. Sancen died at Los Robles Regional Medical Center in Thousand Oaks.

Simi Valley Police Department officers responded quickly to the scene and arrested Almanza, who was found hiding a block away from the crime scene, according to the report.

A Year of Questions Over Competency

The path from arrest to sentencing was not straightforward. On March 6, 2025, a court-appointed mental health expert determined that Almanza was incompetent to stand trial, the Vida Newspaper reported. He was not deemed competent to face proceedings until October 6, 2025.

That seven-month gap reflects a common — and often misunderstood — feature of California criminal procedure. When doubt arises about a defendant's ability to understand the proceedings or assist in their own defense, trials are paused while the defendant receives treatment designed to restore competency. Cases cannot move forward until a judge finds the defendant fit to participate.

Almanza ultimately pled guilty to second-degree murder and the criminal threats counts on August 3, 2026. Under California law, second-degree murder carries a sentence of 15 years to life as a base term, with the prior strike conviction and the weapon-use enhancement adding substantial additional time — resulting in the aggregate term of 39 years and 4 months to life announced this week. Because the sentence includes a life term, Almanza will not be released unless a state parole board grants parole after he becomes eligible.

Family Members Address the Court

Before sentencing, family members provided victim impact statements to the court, including Jose Iglesias-Arroyo, who spoke about the profound personal toll of losing his grandfather.

"To me this is not just a case or a headline, this is my grandfather, this is my family," Iglesias-Arroyo said, according to the Vida Newspaper.

The statements underscored that the tragedy extended beyond the loss of Sancen himself: the same family that arrived that April day to check on Almanza's well-being included the people he threatened, and the grandfather who died was killed in front of relatives.

Why It Matters to Oxnard Residents

While the killing occurred in Simi Valley, cases like this one are adjudicated within the Ventura County Superior Court system that serves all county residents, including those in Oxnard, and prosecuted by the Ventura County District Attorney's Office — the same agency that handles Oxnard's homicide and domestic violence cases.

Family violence remains a persistent concern countywide. Advocates note that situations involving adult family members in crisis — particularly where mental health and violence intersect — can escalate rapidly, as this case did. Resources such as the county's domestic violence hotlines and crisis intervention services exist precisely for these situations, and officials have long encouraged families worried about a relative's mental state to involve professionals rather than confront a crisis alone.

For the Arroyo Sancen family, the sentencing brings a formal conclusion to the criminal case, though not to the grief expressed in court. Almanza will serve his term in state prison. Barring a successful appeal, no further court proceedings are expected in the matter.

The Simi Valley Police Department and emergency responders — including the neighbor with EMT training who rendered aid — were credited in the original account for their rapid response, which led to an arrest within minutes of the attack.