The charge carries a sentence of life without parole upon conviction and is reserved for the most heinous crimes, the New York Post reported Tuesday.
Yoselyn Ortega was charged in the indictment with killing Lucia Krim, 6, and her brother, Leo Krim, 2, on Oct. 25.
She is charged with two counts of first-degree murder and two counts of second-degree murder.
The children's mother, Marina Krim, found them in the bathtub of their Upper West Side apartment, bleeding from slashed throats.
Ortega also allegedly slashed her own throat. She has been in New York-Presbyterian/Weill Cornell Hospital since the incident.
Police said Ortega suffered from mental and financial difficulties and resented the family asking her to work another five hours a week.
Another child, Nessie, 3, was with her mother at the time of the killings and wasn't harmed.
No date has been set for Ortega's arraignment on the charges.
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