Police have arrested and charged the mother of a 1-year-old boy who died in Morris Heights last December with murder.

The boy's mother, Daira Santana-Gonzales, has been charged with murder after the case was ruled a homicide when medical examiners found heroin and other substances in the baby's system.

As News 12 previously reported, Santana- Gonzales lived with the baby's father in their Morris Heights apartment where they first noticed 1-year-old Darwin Gonzalez-Santana not breathing on Dec. 27, 2018. 

MORE: Investigators: Death of toddler in Morris Heights ruled a homicide

Police records say the parents jumped into a taxi to rush him to the hospital, but the baby’s breathing stopped on the way.

They were met by officers who tried to revive him but were unsuccessful. He was pronounced dead at St. Barnabas Hospital.

At that time, police told News 12 there was no sign of physical abuse. But after months of investigating, detectives say they found heroin and fentanyl in the couple's apartment, which they believe was intended to be sold.

Police say Darwin somehow ingested the deadly combination, ultimately causing his death.