(CNN) - Police in New York City have made an arrest in the case of the overdose death of a 1-year-old boy: his mother.
Daira Santana-Gonzalez, 23, was charged last week with second-degree murder, according to a press release from the New York Police Department.
In December, police were alerted to an unconscious 1-year-old in the Bronx and came upon Santana-Gonzalez, her son and the son's father in a taxi outside of their apartment building, according to a law enforcement official with knowledge of the case.
The child was unconscious and unresponsive, the NYPD said in a press release. Officers attempted to revive the boy while transporting him to a nearby hospital, where he was pronounced dead.
The boy died from acute exposure to fentanyl and heroin, among other drugs, according to the New York City office of the chief medical examiner. The death was ruled a homicide.
The official told CNN that drug paraphernalia, including glassine envelopes typically used to package heroin, was found inside the kitchen of the Bronx apartment.
Santana-Gonzalez has been in custody since January, when she was arrested for criminal possession of a controlled substance after narcotics were found in her home, the official said.
There are three people who police are still seeking in the investigation, and police believe that at least one of them is overseas. The NYPD is working with its federal partners to apprehend these individuals, the official said.
An attorney for Santana-Gonzalez did not immediately respond to CNN's requests for comment. She is next scheduled to appear in Bronx Supreme Court on June 6.
CNN's Mark Morales contributed to this report
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