FBI warned prominent US Sikhs of threats after murder of Hardeep Singh Nijjar in Canada

The FBI warned at least three Americans active in the Sikh community that their lives were in danger in the immediate aftermath of the murder of a Sikh activist in Canada last June.

Canadian prime minister Justin Trudeau has blamed the apparent assassination on the Indian government, as assessment that has reportedly been backed by Canadian and US intelligence sources and has created a rupture in Ottawa’s relationship with Indian prime minister Narendra Modi’s government.

The shocking accusation that India carried out an extrajudicial murder on Canadian soil – an allegation that has been denied by India – has prompted a re-examination of threats against Sikh separatists around the world, as well as Sikh activists’ claims of suspicious deaths in the UK and Pakistan in the weeks before the murder.

Related: India-Canada row: Blinken calls on Delhi to cooperate in push for ‘accountability’ over killing

Pritpal Singh, a 69-year-old US citizen who serves as a coordinator for the American Sikh Caucus Committee, confirmed to the Guardian that he and two other associates were called by the FBI just days after the murder of Hardeep Singh Nijjar, the Canadian citizen who was ambushed on 18 June just outside his place of worship in Surrey, British Columbia.

The FBI, which must warn citizens if they learn that their lives are in danger under a legal protection known as a “duty to warn”, initially told Singh that it believed his life was under threat because of unspecified intelligence. A few days later, the FBI offered Singh more specific safety instructions. The Intercept first reported the case.

“Such intimidation of Americans is a form of transnational repression by the Indian government,” Singh said in a statement to the Guardian. “Transnational repression not only threatens individuals but also undermines our democratic institutions, curtails individual rights and freedoms, and challenges the national security and sovereignty of the United States.”

The FBI also warned another American named Amarjit Singh, a 70-year-old New York-based journalist and commentator who said he was first alerted of a possible threat against his life on 22 June. Singh told the Guardian that he was contacted by the FBI as he was returning from a protest against Modi in Washington, during a state visit in which US president Joe Biden hailed the US-India relationship as “stronger, closer, and more dynamic than at any time in history”.

In an interview in which he publicly revealed details of the threat for the first time, Amarjit Singh said the initial call from the FBI was followed up a few weeks later by a longer in-person meeting, at which point he said it was obvious that authorities were warning against a possible threat on his life by India.

“It was a warning. They said no travel, just keep yourself safe,” he said. Amarjit Singh said he only decided to go public with his account after Trudeau revealed Canada’s conclusion about Nijjar’s murder.

New details emerged on Monday about the killing of Nijjar. Citing a security video that captured the murder, the Washington Post reported that at least six men and two vehicles were involved in Nijjar’s killing, in what the newspaper said was a larger and more organised assassination plot than has previously been reported. The assailants fired about 50 bullets, and 34 hit Nijjar.

Nijjar, who was 45, was a leader in the Khalistan movement in Canada, which has called for the creation of an independent Sikh state in the Punjab region of India. The movement has been outlawed in India in the wake of allegations of that supporters of the separatist movement are terrorists.

Media attention has focused largely on Trudeau’s accusation that India was behind the murder. But Canadian authorities are also facing questions about why more was not done to protect Nijjar.

Moninder Singh, a spokesperson for the British Columbia Gurdwaras Council, was one of five people – including Nijjar – who was warned by Canadian authorities in 2022 that their lives were at imminent risk.

“We were never told what the risk was or where it was coming from. But we assumed it was India, because of our activism and outspokenness,” he said. “We expect them to attack us in the media, or character assassination, so this was shocking.”

While he was told to leave his home to protect his young family, Moninder Singh said none of them were offered special protection. Weeks later, Singh was told that the threat against him had dissipated, but the threat against Nijjar – a close friend and mentor – remained.

“There was no other information shared,” Singh said. “While there is an appreciation of Trudeau’s statement, it’s a bit late.”