The owner of a day care where a 1-year-old boy died of fentanyl poisoning and three other children were sickened pleaded guilty Tuesday to federal charges, resolving a case that horrified New York City and underscored the scourge of the nation’s fentanyl epidemic.

Grei Mendez pleaded guilty to one count of conspiracy to distribute narcotics resulting in death and serious bodily injury, one count of possession with intent to distribute narcotics resulting in death and one count of possession with intent to distribute narcotics resulting in serious bodily injury. The three counts carry a minimum of 20 years in prison and a maximum of life in prison.

Prosecutors said the children were poisoned because Mendez, her husband and a co-conspirator chose to operate a large-scale fentanyl packaging and distribution facility inside her day care, which she ran out of a small apartment in the Bronx.