It was a mild Sunday evening in Surrey, a city near Vancouver, British Columbia, and Hardeep Singh Nijjar was ready to drive home after spending the day at his Sikh temple. He had told a friend that he thought he was being followed, but that night, he was just eager to celebrate Father’s Day with his family.
Mr. Nijjar was heading out of the parking lot in his truck when he was ambushed. Two masked gunmen unleashed a burst of gunfire and then sped off in a getaway car. Mr. Nijjar was dead.
The murder that day in June became part of a chain of events that would ricochet around the world, with federal agents in the United States working furiously behind the scenes to untangle an international assassination plot that they believed was directed by someone inside India’s government. The geopolitical implications were huge, and the clock was ticking: The next murder being planned was for someone on U.S. soil.
That explosive tip had come into the Drug Enforcement Administration through an unexpected avenue, according to court records and interviews with people familiar with the investigation — accounts that, taken together, provide a detailed picture of how the episode unfolded.
What followed was an elaborate sting operation involving an undercover D.E.A. agent posing as a hit man and a wad of $15,000 in cash bills, overseen by a sprawling team of investigators who were able to access private text messages between Indian nationals living in India.
This week, federal prosecutors in Manhattan unsealed charges against Nikhil Gupta, a resident of India who was accused of arranging the murder plot in the United States. Officials say the plot targeted a prominent Sikh American activist living in New York City who had been a longtime colleague of Mr. Nijjar, also an outspoken Sikh leader.
Mr. Gupta was arrested in the Czech Republic on June 30 and has been awaiting extradition to the United States, according to a spokesman for the Czech Justice Ministry. Mr. Gupta’s lawyer did not respond to requests for comment.
In a vaguely worded response to the allegations, a spokesman for India’s Ministry of External Affairs said the Indian government had opened an investigation on Nov. 18 after hearing from the United States about “organized criminals, gun runners, terrorists and others.” The Indian government has denied any involvement in Mr. Nijjar’s murder in Canada.
Before the assassination plot spilled into public view, Mr. Gupta was already a known name among some law enforcement officials in the United States, suspected of participating in the sale of heroin and cocaine, according to a person familiar with the investigation. In conversations captured by prosecutors, he had discussed his involvement in international drug and weapons trafficking.
But in late May, when Mr. Gupta called up one of his drug trafficking associates, he was looking for something very different.
Mr. Gupta asked the man if he happened to know anyone who could be hired to carry out a murder in the United States.
What Mr. Gupta did not realize was that the drug trafficker was actually an informant working for the D.E.A.
The D.E.A. had been using the informant in a different case involving Colombian drug trafficking. But Mr. Gupta’s outreach sent the investigation swerving in a new direction, according to people familiar with the investigation.
Mr. Gupta got roped into the plot a few weeks earlier, according to prosecutors, after an Indian government official recruited him to arrange an assassination in New York. Prosecutors said the official, who was not named in the indictment, described working in a government job responsible for intelligence and security management.
The suspected target was Gurpatwant Singh Pannun, a vocal supporter of a Sikh independence movement that India has long seen as a threat. Like Mr. Nijjar, he was pushing for a sovereign state carved out of India for his religious minority group, a dispute rooted in decades of history. It was not clear whether the official in the case was acting alone or with the blessing of others in India’s government.
To win Mr. Gupta’s help, the official promised to get rid of a criminal case looming over him in India, the indictment said. It was not clear what the charges were.
Within a few weeks, the official seemed to make good on the promise. The official reassured Mr. Gupta that the case “has already been taken care of” and that “nobody will ever bother you again,” according to the indictment. Prosecutors said the official even offered to introduce Mr. Gupta to a deputy police commissioner in India.
With the dismissal of his case in India, Mr. Gupta moved ahead with the plan, prosecutors said.
After the D.E.A. found out that Mr. Gupta was looking for an assassin, investigators came up with an idea: A D.E.A. agent would go undercover and play the part of a killer for hire.
The D.E.A. informant introduced Mr. Gupta to the fake hit man, and they agreed on a price for the murder: $100,000.
Mr. Pannun, the man in the cross hairs, had been a lawyer for Mr. Nijjar, the murder victim in Canada. Both men were outspoken critics of India’s leader, Prime Minister Narendra Modi.
In the weeks that followed, the indictment said, Mr. Gupta passed along information from the Indian government official to the hit man, including Mr. Pannun’s home address in New York and details about his daily routine. During a video call, according to prosecutors, Mr. Gupta suggested that the D.E.A. informant could more easily lure Mr. Pannun by pretending to seek legal advice from him.
In early June, the informant asked Mr. Gupta for details about the cash, requesting an advance payment.
The Indian official initially told Mr. Gupta that an upfront fee was impossible and that the full $100,000 payment would transfer 24 hours after the job was done, according to the indictment. But the official eventually relented, providing the name of an associate who would help arrange the funds.
On June 9, the hit man met inside his car with another one of Mr. Gupta’s associates, who showed up with $15,000 in cash. The associate handed over a huge stack of folded up $100 bills.
But throughout the planning, the indictment said, there was one major stipulation from the Indian official: The assassination could not take place during high-level visits between U.S. and Indian officials in late June, matching the time frame when President Biden would be welcoming Mr. Modi to the White House for a state visit.
Given Mr. Pannun’s public profile, Mr. Gupta worried that there could be protests and geopolitical fallout if Mr. Pannun was killed in the United States while Mr. Modi was visiting.
In mid-June, Mr. Gupta told the D.E.A. informant on a call that there was also a “big target” in Canada.
It is not clear whether U.S. officials warned Canadian officials. But six days later, on June 18, Mr. Nijjar was murdered outside his temple.
Hours after the killing, the indictment said, the Indian government official sent a video of Mr. Nijjar’s bloodied body slumped in his car to Mr. Gupta, who passed it on to his associates in New York. Mr. Gupta confirmed to the D.E.A. informant that Mr. Nijjar was the Canadian target he had previously mentioned.
Mr. Gupta told the Indian official that he wished he had personally carried out Mr. Nijjar’s killing and asked for permission to “go to the field,” according to the indictment. The official told him to lay low, saying it was best to stay back.
Their plan to be careful around Mr. Modi’s visit flew out the window. Two days after Mr. Nijjar’s murder, according to the indictment, the Indian official sent Mr. Gupta a news article about Mr. Pannun, saying it was a “priority now.”
Mr. Gupta passed the message on to the man he thought would pull the trigger. Mr. Gupta said there was now “no need to wait” to kill Mr. Pannun, adding, “We have so many targets.” He said Mr. Nijjar was No. 3 or No. 4 on the list.
If Mr. Pannun was in a meeting with others, “put everyone down,” Mr. Gupta said, according to the indictment.
The pressure was mounting, and Mr. Gupta was growing panicked. He demanded frequent updates from his New York associates. Mr. Gupta said they had four jobs to complete before June 29, including three people in Canada.
The Indian official was closely monitoring the operation’s progress. In late June, the official messaged Mr. Gupta to say that Mr. Pannun was not at home — intelligence, the official said, that came from an unnamed “boss,” according to the indictment.
On June 29, Mr. Gupta heard that Mr. Pannun was finally at his home and told the hit man to go for the kill, prosecutors said. Mr. Gupta pressed him to try to “get this done if you have the visuals and if you are sure.”
But there had never been a hit man. The plot that prosecutors say Mr. Gupta had pursued for more than a month could go no further.
The next day, for reasons that are not clear, Mr. Gupta flew from India to the Czech Republic.
As soon as he arrived, he was arrested by Czech law enforcement who were waiting for him at the request of U.S. authorities.
A spokesman for the Czech Justice Ministry said that a decision on Mr. Gupta’s extradition will be made in the coming weeks.
After the case was made public this week, Mr. Pannun said in an interview that he was not surprised by the plot against him, vowing to stay committed to his activism efforts.
“I do not fear the physical death,” Mr. Pannun said. “We are living in the home of the brave and land of the free in America.”
Julian E. Barnes, Kim Barker, Jesse McKinley, Barbora Petrova and Ian Austen contributed reporting.