Full Notification

DATE/TIME: March 18, 2025

INCIDENT: PC 273A(A) - Child Abuse Likely to Produce Great Bodily Harm or Death

LOCATION: 9000 block Arrow Route, Rancho Cucamonga, CA

SUSPECT(S): Christina Veronica Alvarez, 33-year-old resident of Rancho Cucamonga

VICTIM(S): Nathaniel Castro Mendoza, 10-year-old Resident of Rancho Cucamonga 


SUMMARY: The San Bernardino County Sheriff’s Department is providing an update regarding the criminal case involving the death of a 10-year-old child related to fentanyl exposure.

*** UPDATED ON FRIDAY, JANUARY 9, 2026 AT 11:30 A.M. ***

This investigation originated from an incident that occurred in December of 2024, in which a controlled substance, later confirmed to be fentanyl, was inadvertently accessed by the child, resulting in a fatal overdose.

Detectives from the Overdose Response Team determined Christina Alvarez possessed the fentanyl at the time of the incident. Alvarez was arrested and charged with felony child endangerment resulting in death, in violation of California Penal Code section 273a(a).

During previous court proceedings, the defense requested Alvarez be considered for mental health diversion under California law. Mental health diversion is a court-authorized process that allows eligible defendants with qualifying mental health disorders to receive treatment in lieu of traditional criminal prosecution when statutory criteria are met.

On January 9, 2026, after reviewing the request, supporting evaluations, and the circumstances of the case, the court denied mental health diversion. As a result, the criminal case will proceed through the traditional judicial process in accordance with California law.

The Sheriff’s Department recognizes the profound impact this case has had on the victim’s family and the community. Crimes involving fentanyl, particularly those that endanger children, remain a significant public safety concern. This investigation was conducted thoroughly and submitted to the District Attorney’s Office for review and prosecution.

The San Bernardino County Sheriff’s Department remains committed to aggressively investigating cases involving controlled substances and child endangerment and will continue working with prosecutorial and community partners to address the dangers posed by fentanyl.
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SUMMARY: In December 2024, Rancho Cucamonga Station Deputies responded to a 911 call in the 9000 block of Arrow Route in Rancho Cucamonga, in reference to an unresponsive 10-year-old child. Despite life-saving efforts, the child was later pronounced deceased. In February 2025, the San Bernardino County Coroner Division determined the child died from fentanyl and xylazine toxicity.

The San Bernardino County Sheriff's Gang/Narcotics Division's Overdose Response Team (ORT) assumed the investigation. During the investigation, ORT investigators identified Christina Alvarez, a 32-year-old resident of Rancho Cucamonga, who possessed and stored fentanyl in a manner that led to the victim's death. 

The San Bernardino County District Attorney’s Office filed child endangerment charges and issued a warrant for Alvarez in connection to the victim’s death. On March 14, 2025, Alvarez was taken into custody and booked at West Valley Detention Center with a bail amount set at $100,000.

Refer: Overdose Response Team

Station: Gangs/Narcotics Division

Phone No. (909) 387-8400

Case No. 652500068

SHANNON D. DICUS, Sheriff-Coroner
San Bernardino County Sheriff-Coroner Department