September 19, 2024 - SAN QUENTIN – California Department of Corrections and Rehabilitation officials are investigating the Sept. 17, 2024, death of an incarcerated person at San Quentin Rehabilitation Center (SQRC) as a homicide.

At 3:30 p.m., staff responded to an alarm and approached a cell occupied by Mark Squires and Gustavo Lopez. Responding officers observed Squires unresponsive in his cell, and immediately called for medical assistance and 911.

Staff initiated lifesaving measures on Squires and transported him to the prison’s triage and treatment area where treatment continued. Medical staff from an outside medical facility pronounced Squires deceased at 4:04 p.m. No staff or additional incarcerated people were injured.

Lopez was placed in restricted housing pending investigation by SQRC Investigative Services Unit and the Marin County District Attorney’s Office. The Office of the Inspector General was notified, and the Marin County Coroner will determine Squires’ official cause of death.

Squires, 70, was most recently received from Riverside County on Jan. 28, 2000, to serve life with the possibility of parole for lewd or lascivious acts with a child under 14 with force or violence and failure to register/specific sex offense.

Gustavo, 36, was most recently received from Riverside County on Jan. 6, 2020, to serve 13 years, four months for kidnap, second striker; corporal injury on specific persons resulting in traumatic condition, second striker; and false imprisonment with violence, second striker.

SQRC is California’s oldest correctional institution. It opened July 1852 and houses more than 3,000 minimum-, medium-, and maximum incarcerated persons. SQRC offers academic classes and vocational programs and employs approximately 1,750 people.

Source: CDCR