San Bernardino County woman charged in 10-year-old boy's fentanyl poisoning death

SAN BERNARDINO COUNTY, Calif. - A Rancho Cucamonga woman has been arrested and charged in the death of a 10-year-old boy due to fentanyl poisoning, according to the San Bernardino County Sheriff's Department.

What we know:

In December 2024, deputies responded to a 911 call regarding an unresponsive child in Rancho Cucamonga. 

Despite efforts to save him, Nathaniel Castro Mendoza was pronounced dead at the home. 

The San Bernardino County Coroner Division later determined the cause of death to be fentanyl and xylazine toxicity. 

32-year-old Christina Alvarez was identified as possessing and storing the fentanyl that led to his death.

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She was arrested on March 14 and booked at West Valley Detention Center.

Alvarez is charged with child endangerment. Her bail is set at $100,000.

What we don't know:

A motive was not disclosed. 

It's unclear what Alvarez's relationship was with Mendoza.