One inmate is dead and another is under investigation for murder following a violent altercation earlier this month at the California Medical Facility in Vacaville, according to California Department of Corrections and Rehabilitation (CDCR) officials.
Prison official say a fight broke out around 7:20 p.m. on Jan. 4, between inmates Joe Duty Jr. and Stephenson Choi Kim in one of the prison’s housing units.
“Kim was found unconscious and staff immediately responded, initiating life-saving measures on Kim and activating 911,” a news release from the CDCR states. “Kim was taken immediately to the prison’s triage and treatment area and subsequently transferred to an outside medical facility. Duty was medically evaluated and placed in restricted housing.”
On Monday, Kim was pronounced dead at the outside medical facility.
Duty remains in restricted housing pending an investigation by the CMF Investigative Services Unit and the Solano County District Attorney’s Office. The Office of the Inspector General has been notified, officials noted.
Kim, 45, was most recently received from Orange County on May 23, 2012. He was sentenced to life without the possibility of parole for first degree murder and attempted first degree murder with enhancements for the intentional discharge of a firearm causing great bodily injury or death and the discharge of a firearm.
According to the Orange County Register, Kim was a gang member and was convicted of first-degree murder in March 2011 for a March 13, 2004, shooting spree at the 5th Wave Cafe that killed 21-year-old Venus Hyun and injured four others. Kim initially faced the death penalty, the paper reported, but jurors deadlocked 7-5 against recommending that Kim be executed.
Prosecutors said Kim opened fire at the cafe because he thought one of the victims had ties to a rival gang that had beaten him up.
Duty, 30, was most recently received from San Joaquin County on Feb. 14, 2025. He was sentenced to 14 years for rape with force, violence or fear, of a minor 14 years of age or older and lewd or lascivious acts with a child under 14 with force, violence or fear.
California Medical Facility is one of two prisons in Vacaville. It was established in 1955 to provide a centrally located facility to meet the medical, psychiatric, and dental health care needs of males incarcerated within CDCR. It is a medium-security medical facility.