It was a grubby, cash-in-a-car conspiracy with international implications: the thwarted assassination of an Indian separatist in New York City.
That plot was outlined on Wednesday by federal prosecutors in Manhattan who charged an Indian national with an attempt to kill a U.S. citizen who is a Sikh separatist. The indictment says the plan was devised by an Indian agent, allegations that could complicate the delicate relations between Washington and New Delhi.
The murder-for-hire charges against the man, Nikhil Gupta, 52, were announced by the Justice Department days after American officials had expressed concerns to the Indian government about the suspected assassination plot against the separatist.
And the charges came just months after Prime Minister Justin Trudeau of Canada accused the Indian government of involvement in the June killing of another Sikh separatist, Hardeep Singh Nijjar, in Vancouver, British Columbia. American intelligence agencies provided information to the Canadian government about that killing.
The target in New York was identified by American officials as Gurpatwant Singh Pannun, who is general counsel for the New York-based group Sikhs for Justice. Mr. Pannun is an outspoken proponent of independence for the northern Indian state of Punjab, which is home to a large number of Sikhs, a powerful but minority group in the nation.
The indictment said that the supposed hit man hired to kill Mr. Pannun was in fact a federal agent.
After the killing in Vancouver, F.B.I. agents warned a number of Sikh leaders around the United States about potential threats against them.
Adrienne Watson, a spokeswoman for the National Security Council, said Wednesday that after the Biden administration learned that Mr. Gupta had “credibly indicated” he had conspired with an employee of the Indian government, the White House engaged “in direct conversations with the Indian government at the highest levels to express our concern.”
“The government of India was clear with us that they were taking this seriously and would investigate,” Ms. Watson said in a statement. “We are providing information to the government of India to aid in their internal investigation. We will continue to expect accountability.”
President Biden directed William J. Burns, the C.I.A. director, to visit India to discuss the suspected assassination plot and press the Indian government to hold those involved responsible, according to U.S. officials familiar with the events. Mr. Biden himself raised the issue directly with Prime Minister Narendra Modi when they met at the Group of 20 summit in September.
Indian’s Ministry of External Affairs said Wednesday that the United States had “shared some inputs pertaining to nexus between organized criminals, gun runners, terrorists and others” and that the government had convened a committee to investigate.
Federal prosecutors in New York said that the plot involved several accomplices, including the Indian government official, who had a background in law enforcement.
That individual, who was not identified, is accused of recruiting Mr. Gupta, who prosecutors say then hired a hit man to kill Mr. Pannun and provided personal information about him, including his home address in New York City and details about his daily activities.
That for-hire killer, however, turned out to be an “undercover U.S. law enforcement officer,” according to the U.S. attorney for the Southern District of New York.
Mr. Gupta was detained by authorities in the Czech Republic in late June, according to the Southern District. He faces charges of “murder-for-hire and conspiracy to commit murder-for-hire,” prosecutors said, with each count carrying a potential sentence of 10 years in prison.
It was not immediately clear Wednesday who was representing Mr. Gupta.
The charges in New York came after an autumnal diplomatic skirmish between India and Canada, after Mr. Trudeau accused the Indian government of involvement in the killing of a Canadian citizen on Canadian soil in June.
The allegation was met with stern denials from Indian authorities.
Mujib Mashal contributed reporting.