Indian diplomat Devyani Khobragade’s status as Special Advisor to the U.N. entitled her to diplomatic immunity, according to a letter from United Nations Assistant Secretary General for Legal Affairs Stephen Mathias. Ms. Khobragade’s lawyer Daniel Arshack submitted the letter in a U.S. court along with his motion to dismiss the indictment against her.

Mr. Arshack said the 39-year-old diplomat was credentialed as Special Advisor to the U.N. from August 26 to December 31, 2013, making her immune from arrest on December 12 on visa fraud charges.

He said Ms. Khobragade was appointed advisor ahead of Prime Minister Manmohan Singh’s visit to the U.N. General Assembly session.

The letter states that according to the Convention on the Privileges and Immunities of the U.N. adopted by the General Assembly, “...representatives of members to the principal and subsidiary organs of the United Nations and to conferences convened by the United Nations shall, while exercising their functions and during their journey to and from the place of meeting, enjoy the... privileges and immunities” set forth under sections of the Convention unless the person is a “representative in a state of which s/he is a national or of which s/he has been a representative.”

The letter said the expression representatives “shall be deemed to include all delegates, deputy delegates, advisers, technical experts and secretaries of delegations.”

It clarified that application of the rules of immunities in any specific situation “would depend on the facts and circumstances of the specific situation.”

Ms. Khobragade was strip-searched and held with criminals after her arrest, triggering a diplomatic row between India and the U.S. After her indictment on visa fraud, she returned to India in January after the U.S. State Department allowed her to leave the country.