Indian diplomat Devyani Khobragade has sought dismissal of the visa fraud case against her on the ground that the indictment was filed in a court here a day after the US accorded her full diplomatic immunity and the country did not have criminal jurisdiction over her.

Khobragade's lawyer Daniel Arshack submitted her reply, in a federal court here, to Manhattan federal prosecutor Preet Bharara's memorandum that had opposed her motion to dismiss the indictment.

Khobragade was present in the US at the time the indictment was returned and "the State Department's recognition of her diplomatic position with the Permanent Mission of India to the United Nations conferred diplomatic immunity upon her requiring that the entire 'proceeding or action' be dismissed," Arshack said in his 17-page motion filed late yesterday.

"The instant indictment was returned and filed with the Court prior to Khobragade's departure (from the US) when she was still recognised as a diplomat and still imbued with diplomatic immunity...The prosecution could not then and cannot now proceed further on that invalid instrument," Arshack said.

He, however, acknowledged that the prosecution is not prevented from prosecuting Khobragade in future but insisted that the current case against her be dismissed since she had diplomatic immunity when the indictment was filed.

Arshack's motion comes a week after Bharara submitted a US State Department declaration that Khobragade did not enjoy immunity from arrest or detention at the time of her arrest and she does not presently enjoy immunity from prosecution for the crimes charged in the indictment.

Arshack said the indictment must be dismissed because the immunity bestowed upon Khobragade "applied retroactively".

The court could now order to hear arguments on the motions.

Khobragade, 39, was arrested on December 12 on visa fraud charges, strip-searched and held with criminals, triggering a row between the two countries with India retaliating by downgrading privileges of certain category of US diplomats among other steps.

Khobragade was indicted on visa fraud and making false statements by a US grand jury. She returned to India after she was asked to leave the US by the State Department.

Arshack said the "pertinent" facts in the case are that Khobragade was given full diplomatic status by the Department of State at 5:47 pm (local time) on January 8 when it approved her appointment as Counsellor to the Permanent Mission of India to the UN.

The grand jury returned the indictment on January 9 "after she was already cloaked with diplomatic immunity".

"It is acknowledged that the prosecution is not forever precluded from prosecuting the defendant. Our application is only that this proceeding must be dismissed. The prosecution is clearly legally able to seek a new indictment at this time or at some point in the future now that Khobragade no longer possesses such diplomatic status and immunity, but it may not proceed further with this case," Arshack said.

He said in accordance with the Vienna Convention on Diplomatic Relations, the case should have been dismissed on January 9, because Khobragade did not become a "former" diplomat until later that evening when she left the country.

"The proceeding must be dismissed for lack of jurisdiction because at the time the indictment was issued, the US did not have criminal jurisdiction over Khobragade," he said.

Arshack rebutted Bharara's allegation that Khobragade had employed her domestic worker in her personal capacity and not as India's Deputy Consul General in New York, which made her not immune to criminal prosecution.

"The prosecution goes to great lengths in its opposition to make inapposite distinctions between the immunity conferred upon consular officials versus diplomats under the respective Vienna Conventions as the ostensible basis to deny the requested relief.

Such distinctions are a clear effort to obfuscate, are irrelevant and do not assist the Court in resolving this matter," Arshack argued.

"For all intents and purposes, she (Khobragade) was a diplomat present in the receiving country and entitled to full diplomatic privileges and immunities when these events transpired. As such, she could not have been arraigned by Your Honor on the indictment even if she had appeared in Court because she was still an active diplomat entitled to immunity from criminal prosecution," the lawyer said.

Seeking to bolster his argument, Arshack has given a timeline of facts and sequence of events as the case unfolded to demonstrate that because "Khobragade was immune from prosecution at the time the indictment was returned", this case should have been dismissed on January 9.

"Here, the sequence of events to be examined for resolution of the motion is critical. The question is not whether the prosecution may bring a case against Khobragade now that she is a 'former' diplomat: it can. But, it cannot do so based upon an indictment that was obtained while she was an active diplomat cloaked in immunity, as she was on January 9, 2014 when the grand jury voted a true bill," he said.

"So, the factual analysis for the Court to resolve is at what point Khobragade's diplomatic status was revoked such that she was converted to "former" diplomat status," Arshack said.

He has submitted seven supporting documents with his motion as proof that Khobragade had immunity when she was appointed Deputy Consul General at the Indian Consulate in the city and following her transfer to India's Permanent Mission to the UN.

Among the supporting documents is a screen shot of the UN Protocol and Liaison Service listing of Khobragade having been accredited as an advisor to the UN for the entire General Assembly meeting.

He has also submitted a declaration by UCLA Law School and Harvard Law School graduate professor Kal Raustiala, an expert on the application of privileges and immunities to diplomats, who said that Khobragade was immune from criminal jurisdiction of the US beginning the evening of January 8 when she was accorded full diplomatic status by the State Department untill her departure from the US on the night of January 9.

Arshack reiterated that Khobragade's arrest was "illegal and should never have occurred", adding that the subsequent indictment was "likewise tainted and must, for this additional reason be dismissed".

He said when a diplomat is cloaked with immunity at the commencement of an action, that action must be dismissed even if the diplomat is later terminated from the diplomatic post.

Further, he said, even if Khobragade enjoyed only immunity only for "officials acts", that immunity too "precluded her arrest and indictment for the acts alleged by the prosecution."

Citing the Vienna Convention rules, Arshack said that helping and assisting nationals, both individuals and bodies corporate, of a sending state are legitimate consular functions.

In assisting her domestic worker in the preparation an A-3 visa application to travel to the US, Khobragade was performing official functions.

Even the employment contract, which prosecutors have said is false has been "submitted in support of the visa application" and so come under Vienna convention rules, the lawyer said.

"The prosecution conflates the issues before the Court by citing legally and factually inapposite case law for their unsupportable position. The truth is that there are no cases on the distinct legal issue of whether the acts of submitting a visa application and making statements to the US fall within a consul official's 'exercise of consular functions'," Arshack said.

"This is an issue of first impression, which must be decided by this Court if it finds that Khobragade was not cloaked with full diplomatic immunity," he added.