A Sacramento County jury has convicted an Elk Grove man of first-degree murder for stabbing his roommate 54 times inside the home they shared, rejecting his claim that he acted in self-defense. Ricky Sims is scheduled to be sentenced October 23, 2026, and faces a maximum of 26 years to life in prison for killing 36-year-old Marya Guillen in August 2021.
Guillen was found dead in her bedroom inside a home in the 8900 block of Sierra Street, near Elk Grove Florin Road and Elk Grove Boulevard, according to ABC10. Officials say she suffered 54 sharp force wounds in total, with 45 of them concentrated on her face, head, neck and extremities. As reported by FOX40, Sims called 911 himself the day of the killing and told the dispatcher he had stabbed Guillen in self-defense.
The case actually reached police through an unrelated-sounding call. Elk Grove Police Department officers responding to what began as a 911 medical aid call arrived at the home around 8:23 a.m. on August 15, 2021, according to the Elk Grove Tribune. When officers reached the residence, they encountered Sims at the front door, and when he refused to follow commands or let them inside, police deployed a less-than-lethal force measure to detain him before entering the home, the outlet reported. Officers then found Sims covered in blood, per FOX40's reporting.
From the Scene to the Jail
Following his detention, Sims was taken to a local hospital for evaluation and treatment of injuries sustained during the police encounter before being transferred and booked into the Sacramento County Main Jail, ABC10 reported at the time. Early coverage of the case, including reporting from CBS Sacramento, described Sims and Guillen as romantic partners, though court proceedings have since confirmed the two were roommates sharing the home. The Sacramento County Coroner's Office identified Guillen, of Elk Grove, as the victim days after the killing.
Nearly five years passed between the 2021 arrest and this month's conviction, a gap that reflects the lengthy pretrial process such serious felony cases often face in Sacramento County courts. A jury ultimately found Sims guilty of first-degree murder and determined he personally used a deadly weapon in the killing, according to FOX40.
Why the Self-Defense Claim Failed
Under California's jury instructions on self-defense, known as CALCRIM 505, a defendant must show he reasonably believed he faced an imminent threat of death or great bodily injury and used no more force than necessary to counter it. The sheer scale of Guillen's injuries — 54 sharp force wounds — undercut that standard in the eyes of the jury, according to legal analysis from the Kraut Law Group.
California Penal Code Section 187 sets a mandatory baseline sentence of 25 years to life in state prison for a first-degree murder conviction, per FindLaw. Because the jury found Sims personally used a deadly weapon, he also faces a consecutive one-year enhancement under Penal Code Section 12022(b)(1), pushing his maximum exposure to 26 years to life. Sims is set to learn his fate at sentencing on October 23.
