VENTURA, Calif. — A 36-year-old Simi Valley man has been sentenced to serve 51 years to life in state prison for the brutal stabbing murder of his girlfriend inside their home, an attack witnessed by the victim's five young children, public safety officials and county prosecutors announced.
Ventura County District Attorney Erik Nasarenko confirmed that Ramon Joseph Rivas (DOB 02/17/90) received the maximum prison term following formal sentencing proceedings in Ventura County Superior Court.
Rivas previously entered a guilty plea on May 20, 2026, to second-degree murder in the death of Jessica Marie Tinoco. In addition to the primary murder charge, Rivas admitted to numerous special allegations, aggravating factors, and prior criminal strike enhancements under California law, including the personal use of a deadly weapon, commission of a crime involving great violence, targeting a particularly vulnerable victim, and serving prior state prison terms.
Domestic Dispute Escalates to Fatal Stabbing Inside Family Home
According to court records and investigative details released by the Ventura County District Attorney’s Office, the fatal assault occurred on the evening of September 27, 2024, at a residential property in Simi Valley.
Officers with the Simi Valley Police Department dispatched to the home following urgent 911 calls reporting an active domestic stabbing in progress. Upon arrival at the scene, officers encountered Rivas walking out through the front door shirtless with wet blood covering his hands and upper torso. He was immediately taken into custody without further incident.
Upon making entry into the residence, responding officers discovered Tinoco lying face up on the floor just inside the front entrance, suffering from severe, bleeding stab wounds to her face, abdomen, and arms. Officers located a bent, blood-stained kitchen steak knife resting on the living room floor alongside extensive physical evidence of a violent struggle throughout the home.
Paramedics with American Medical Response provided emergency medical care at the scene before rushing Tinoco by ambulance to Los Robles Regional Medical Center in Thousand Oaks. Despite emergency surgical interventions by hospital trauma physicians, Tinoco succumbed to her injuries and was pronounced deceased. Medical examiners later confirmed she suffered multiple knife strikes, including four distinct fatal wounds.
Witness statements gathered by Simi Valley Police detectives revealed that a verbal domestic dispute erupted between Rivas and Tinoco inside the home. As the argument escalated, Rivas walked into the kitchen, retrieved a heavy steak knife, and launched a physical attack against Tinoco directly in front of her five children. The children managed to flee the house as the violence unfolded to seek help from neighbors.
Prosecution Statements and Formal Court Enhancements
The homicide prosecution was handled by Senior Deputy District Attorney John Barrick, a veteran prosecutor assigned to the District Attorney’s Office Major Crimes Homicide Unit.
Reflecting on the resolution of the criminal case and the permanent trauma inflicted on the surviving family, SDDA Barrick emphasized that no legal plea can undo the devastating loss suffered by the young children.
"The defendant’s willingness to take responsibility for his horrendous crime doesn’t excuse what he did to the victim and her family," Senior Deputy District Attorney John Barrick stated in an official press release released by Communications Manager Joey Buttitta.
Under the final court judgment, Rivas admitted to extensive criminal charges and statutory enhancements under the California Penal Code and California Rules of Court:
- California Penal Code § 187(a): Second-Degree Murder
- California Penal Code § 12022(b)(1): Special Allegation – Personal Use of a Deadly Weapon
- California Penal Code § 667S3 / § 667(a)(1): Third Strike and Serious Violent Felony Priors
- California Rules of Court 4.421: Aggravating Factors – Crime Involving Great Violence, Vulnerable Victim, Pattern of Violent Conduct, and Prior State Prison Terms
Rivas remains in custody at the Ventura County Pre-Trial Detention Facility awaiting final administrative transfer to the California Department of Corrections and Rehabilitation, where he will serve his 51-year-to-life sentence.
Sources
Ventura County District Attorney's Office Official Release (Release No. 26-107)