San Bernardino County has agreed to a $1.75 million settlement in a wrongful-death lawsuit over the killing of an inmate by his own cellmate at West Valley Detention Center in Rancho Cucamonga, a case that put fresh scrutiny on how the county houses mentally ill detainees alongside men with violent criminal histories. Adam Preston Adams, 56, who suffered from schizophrenia, was killed on May 21, 2023, by cellmate Marco Antonio Lopez-Hernandez.
According to The Press-Enterprise, the settlement was reached in a federal lawsuit filed by Adams' daughter, Jennifer Quintero, who sued San Bernardino County after her father's death. The suit was filed July 11, 2024, in U.S. District Court in Riverside, and Judge Kenly Kiya Kato dismissed the case on October 7, 2026, after the settlement agreement was finalized. As of October 9, 2026, San Bernardino County had not confirmed the settlement amount, per the same report.
Lopez-Hernandez, 29 and from Upland, now faces a murder charge in Adams' death, to which he has pleaded not guilty and not guilty by reason of insanity. He is separately accused of obstructing an executive officer and attempting to remove a peace officer's weapon, charges to which he has also entered dual pleas of not guilty and not guilty by reason of insanity, the station's report notes. The San Bernardino County Sentinel reported in May 2023 that Lopez-Hernandez had been held at West Valley since March 29, 2023, on $80,000 bail stemming from a prior arrest by Upland police on charges including petty theft, resisting arrest, and attempting to remove a firearm from an officer. The Sentinel also detailed the physical mechanics of the attack, reporting that Lopez-Hernandez slammed Adams' head onto the concrete floor of their cell; a deputy found Adams unresponsive at approximately 4:54 a.m.
Lawsuit Alleges Deputies Knew of the Risk
The wrongful-death lawsuit alleges that correctional deputies failed to protect Adams from Lopez-Hernandez despite knowing of his violent history before placing the two men in the same cell, per the Press-Enterprise's report. San Bernardino County has denied negligence, writing in court filings that the plaintiff had not identified deficient policies or explained how any such policies caused Adams' death, the outlet reported.
Quintero was represented by attorneys Denisse Gastélum and Christian Contreras. Gastélum said the settlement represents an important step toward justice but that no amount of money can bring Quintero's father back, according to the same account. Gastélum also said that people do not lose their constitutional rights when they enter a jail.
The lawsuit cites a broader pattern of violence inside county jails, noting that six inmates died from attacks by other inmates in county facilities from June 2018 through March 2023, per the Press-Enterprise's reporting on the suit's claims.
Echoes of a 2019 Killing at the Same Jail
Adams' death bears a close resemblance to another case at the same facility. Prison Legal News reported in March 2024 that mentally ill detainee Robert Vernon Sutton, 58, was beaten to death in March 2019 by cellmate Lager George Reid, 26, after deputies housed the two together despite Reid's documented history of violence, which reportedly included a prior assault on a jail nurse. Sutton's family received an $857,500 wrongful-death settlement in April 2021.
The same outlet reported that 12 detainees died in San Bernardino County jails during 2023 — 50% more than the county's 15-year annual average of about 8.27 deaths per year — including four deaths in December 2023 alone. An analysis of state public records published by CalMatters found that 216 people died in custody in San Bernardino County between 2011 and 2022, and that the Inland Empire accounted for nearly 19% of California's in-custody deaths despite representing just 12% of the state's population.
County Jails Remain Under Scrutiny
San Bernardino County's jail system has operated under some degree of federal oversight since a December 2018 consent decree in Turner v. County of San Bernardino established court monitoring of medical, dental, and mental health care across four county lockups, Prison Legal News reported in November 2024. A federal court partially released the county from medical monitoring in July 2024, while mental health care remained under review, according to the outlet.
The $1.75 million settlement adds to a growing list of financial judgments tied to San Bernardino County's jails. Prison Legal News reported in March 2026 that the Ninth Circuit U.S. Court of Appeals affirmed a $3.84 million federal jury verdict against the county over the August 2022 death of detainee William Enyart, who died on August 1 from untreated alcohol-withdrawal symptoms; his family had called 911 on July 27. Years earlier, the Inland Valley Daily Bulletin reported in July 2017 that the county paid $2.5 million to settle civil rights lawsuits brought by 32 current and former inmates alleging physical abuse and torture by deputies at West Valley Detention Center, following a 2014 federal investigation into guard conduct.
West Valley Detention Center is one of the largest county jails in California, operating 3,347 beds and processing between 50,000 and 60,000 inmate bookings and releases annually, according to official facility records. Another in-custody death at the facility involved the unresponsive inmate case involving Elizabeth Ardon.
