New York police are investigating a mother they believe locked herself inside a Manhattan restaurant bathroom with her son and refused medical attention while the boy lost consciousness and later died, The New York Times reported.

On Tuesday morning, 35-year-old Latisha Fisher was charged with second-degree murder for the death of her 20-month-old son Gavriel Ortiz-Fisher, who was found unconscious and foaming at the mouth when employees at 5 Boro Burger in Midtown were forced to use a key to open the restroom door.

Police say Fisher walked into the Sixth Avenue burger joint on Monday and at some point entered the bathroom with her son and locked the door, The NY Times reported.  

After a while restaurant workers became concerned and used a key to open the door. Gavriel was found unresponsive on his mother's lap.

" 'I put my hand over his mouth to put him to sleep,' " the mother allegedly said when asked what happened, staff told CBS New York.

Later on, Fisher allegedly said, "The devil made me do it," unnamed sources told the station.  

Paramedics were called at around 2:30 p.m. and Gavriel was rushed to a hospital in cardiac arrest. He was pronounced dead at Bellevue Hospital Center. An autopsy is to determine an official cause of death.

As of Tuesday investigators did not say if child protective services had prior contact with Fisher, who was described by neighbors where she lives in lower Manhattan as a devoted mother.

"She was crazy about that baby; she always took care of him," Josefina Deleon, who lives at the Samuel Gompers Houses on the Lower East Side, told The NY Times. "It hurts."