Reuters reports that a nanny from New York City is accused of killing two children who were found death in their parents’ apartment in Manhattan. Yoselyn Ortega was charged with two counts of first and second degree murder by a grand jury in New York City.

Marina Krim returned to her home in the Upper West Side on October 25 and found the lifeless bodies of her children Lucia, 6, and her brother, Leo, 2, in the bathtub. Yoselyn Ortega, the nanny who was supposed to take care of the children, attempted to kill herself in front of Krim; she was rescued and is now under police surveillance at the hospital.

The 50-year-old woman was arrested 10 days ago after police officers, who interviewed her in the hospital room, agreed that she should be indicted on murder charges. Investigators still haven’t managed to determine what might have pushed Ortega to act the way she did, but they will continue to search the house for further evidence.

The Krims never suspected Ortega could be capable of murder. The latter had been working for them for two years and was a close friend of the family. In fact, she lived with her son and sister near her employers’ apartment and constantly displayed an irreproachable behavior. She gained her U.S. citizenship more than a decade ago, so the Krims had no reason to suspect her of murder when they agreed to hire her.

On the day of the killing, Marina was supposed to meet Ortega and her two children at a local dance studio. She returned home and asked the doorman if the nanny left the house because the lights were out. When she entered the house, she found the two children in the bathroom and later on, encountered Ortega. The father, Kevin Krim was returning home from a business trip at the time of the killing.