Kilogram of fentanyl found in NYC day care center where 1-year-old boy died of apparent overdose

1-year-old Nicholas Dominici died of an opioid overdose last week .

The day care center owner pleaded not guilty on Sunday to murder charges in the death.

A man who rented a room inside the Bronx apartment, Carlisto Acevedo Brito , 41 , is awaiting arraignment on the same set of charges.

Fentanyl , a synthetic opioid that is up to 50 times stronger than heroin, is a primary driver of soaring overdose deaths.