The Central Bureau of Investigation (CBI), in a 30-page affidavit, said that Nupur Talwar "is likely to tamper with the evidence and abscond in case she is released on bail".
"The evidence so far recorded before the trial court is incriminating and hence there is every likelihood that the petitioner (Nupur Talwar) may abscond in the event of release on bail," the investigating agency told the apex court, opposing her plea for bail.
Nupur Talwar has challenged the May 31 Allahabad High Court order rejecting her plea for bail. She was taken into custody April 30 and lodged in Dasna jail in Ghaziabad.
The CBI in its affidavit said that the accusation of "double murder and destruction of evidence" against Nupur Talwar were "well founded and evidence has started coming in".
The CBI said that it had already moved the high court challenging a magistrate court's order granting bail to her husband and co-accused Rajesh Talwar.
The investigating agency said that "the seriousness of the offence is a valid ground to refuse bail".
The affidavit said that Nupur Talwar "tried her level best to remain away from the process of law and she surrendered only after the direction passed by the this (apex) court".
The CBI said that Nupur Talwar was not a "law abiding citizen and is accused of committing double murder and is facing trial for the same and does not deserve to be released on bail and the order of the court below refusing to release her on bail does not deserve any interference".
Aarushi, 14, was found murdered at her parents' Noida residence May 16, 2008. The body of Hemraj was found the next day on the terrace of the house.
A CBI court has charged the Talwars under sections 302/34 (murder with common intention) and 201 (destruction of evidence with common intention) of the Indian Penal Code (IPC). In addition to these, the court charged Rajesh Talwar under section 203 (giving false information in respect of an offence committed) of the IPC.