Queens District Attorney Richard Brown said Ms Pardas' actions are "beyond comprehension".
An Indian-origin woman faces 25 years to life in prison in the US for strangling her 9-year-old step-daughter to death as federal prosecutors charged her with murder and her ex-husband for obstructing the investigation.
Arjun Shamdai Pardas, 55, was arraigned on Sunday before Queens Criminal Court Judge Gerald Lebovits on a criminal complaint charging her with one count of second-degree murder - an intentional killing that is not premeditated - of Ashdeep Kaur.
Ms Pardas, who faces up to 25 years to life in prison if convicted, was ordered held without bail.
She will return to court on September 2.
Ms Pardas' former husband Raymond Narayan, 65, is being held on charges of obstructing governmental administration and faces up to a year in jail and a $1,000 fine if convicted.
Queens District Attorney Richard Brown said Ms Pardas' actions are "beyond comprehension" and she will be brought to book.
"This is a horrifying case of a child, a defenceless nine-year-old, who was left in the care of her stepmother who allegedly strangled her to death. Her actions, if true, are beyond comprehension and must be severely punished," Brown said.
Queens Assistant District Attorney Michael Curtis said Ms Pardas repeatedly and on numerous occasions threatened to kill the victim, "most recently doing so this past Tuesday. On Friday, she made good on that threat."
Ashdeep Kaur had arrived in the US from India three months ago and was living with her father Sukhjinder Singh and Ms Pardas in an apartment in Queens that was shared with another couple.
The housemate had seen Ashdeep Kaur go in the bathroom with Ms Pardas, who later came out alone and left the building. She allegedly said that Ashdeep Kaur was taking a bath.
The charges added that on the evening of August 19, the housemate saw Ms Pardas leaving the house along with Mr Narayan, and her two grandchildren aged 3 and 5.
When the housemate asked Ms Pardas about Ashmeer Kaur, she allegedly said that the child was in the bathroom and was waiting for her father to pick her up.
The housemate had observed that the bathroom light had been on for several hours and called Ashdeep Kaur's father.
She was instructed to break open the bathroom door at which time she found Ashdeep Kaur's dead body in the bathtub. There were several bruises on her body.
A report filed by the Medical Examiner's Office determined that the cause of death was manual strangulation.
It is further alleged that New York Police Depratment detectives went to Mr Narayan's residence and found him, Ms Pardas and the two grandchildren inside the apartment.
Ms Pardas refused to come out and refused to allow entry to the police for over one hour.
Mr Narayan later opened the door and both defendants were apprehended.
Ashdeep Kaur's relatives said the young girl had been previously allegedly abused by Ms Pardas, who had been entrusted with her care while Mr Singh worked in a local restaurant.