Nearly three years after an Indian family of four froze to death in Canada during an ill-fated attempt to enter the US, two men are facing trial, accused of trying to help smuggle them across the border.

It was a backpack with child’s clothing and toys that first worried US Border Patrol agents.

That winter morning in January 2022, after a fierce blizzard, authorities had arrested a man driving a van near the US-Canada border, suspecting him of smuggling migrants.

Along with the driver, border guards picked up seven Indian nationals. One was carrying the backpack, but there were no children.

A family with two children had been with the other migrants as they made their way across the border at night, border agents were told, but they had become separated.

A search was launched and Canadian police found the bodies of Vaishaliben Patel, her husband Jagdish and their two young children, 11-year-old Vihangi and three-year-old Dharmik, in a Manitoba field just 12m (39ft) from the US border.

It is believed that the family – who had travelled on visitor visas from their home village in western India to Toronto, Canada – were trying to cross into the US when they were caught in the blinding blizzard with a bone-chilling cold that hovered below -35C (-31F).

Harshkumar Ramanlal Patel (who is not related to the deceased family) and Steve Anthony Shand are accused of helping them make the fatal journey.

They each face charges of human trafficking, criminal conspiracy and culpable homicide not amounting to murder in the US state of Minnesota, with their trial set to begin on Monday with jury selection. Both have pleaded not guilty.

Court documents filed in the case reveal an alleged complex, global web behind human smuggling operations that are designed to get foreign nationals into North America.

In this alleged case, it began with thousands of dollars in payments to illegal immigration agents in India, who then connected those eager to move abroad with a network of smugglers based in the US and Canada.

Since the Patel tragedy, at least two more families have died trying to unlawfully cross the US-Canada border.

Immigration experts fear clandestine smuggling networks will be used more by undocumented migrants in the coming years, in light of Donald Trump’s incoming administration and its plan for mass deportations.

Mr Shand was the van driver, arrested on the same day the Patels’ bodies were discovered.

Police say they found him with a 15-passenger van near the border of Minnesota in the US and Winnipeg in Canada, with two Indian nationals who were unlawfully in the US.

Five others – all from Gujarat, the Patels’ home state in India – were found walking towards where Mr Shand was apprehended.

One of them, identified in documents only as VD, told officers that the group had walked across the border at night. It took them 11 hours and they had expected to be picked up by someone once in the US.

VD told authorities that he paid “a significant sum” of US$87,000 (£68,519) to an organisation in India that arranged for him to enter Canada – under the guise of a fraudulently obtained student visa – and later help him illegally enter the US.

Meanwhile, Mr Patel is accused of being a key organiser of the smuggling effort.

He managed a casino in Orange City, Florida, according to testimony provided by Mr Shand to the authorities after his arrest. Mr Patel, who police say also went by the nickname “Dirty Harry”, does not have legal status in the US and has been refused a US visa five times, per government records.

He is believed to have recruited Mr Shand to transport people illegally across the US-Canada border, communicating with him regularly about travel logistics, rental car arrangements, hotel bookings and pick-up locations for Indian nationals.

The two had discussed the severe weather on the day the Patels’ bodies were found, according to court documents, with Mr Shand texting Mr Patel: “Make sure everyone is dressed for blizzard conditions please.”

The Patel family are believed to have been connected to the two men through a contact in Toronto, who was connected to the India-based organisation that used student visas to grant people entry into Canada and then smuggle them into the US.

A lawyer for Mr Patel said in a statement to the BBC that: “We look forward to the trial and the chance to show that Mr Patel took no part in this tragic event.”

No other lawyers involved in the case commented.

Two Indian nationals in Gujarat have also been arrested by police in connection with the Patels’ death. Indian police said the men were “illegal immigration” agents.

A related investigation into this India-based operation has revealed that, once crossing into the US, some Indian nationals would then be transported to a Chicago restaurant chain – unnamed by investigators – where they worked for “substandard wages” to pay off debts they owed to the smugglers.

It is unclear what the Patels’ final destination was, or why they had made the treacherous and unlawful journey.

Shortly after their death, residents from their home village in India told the BBC that they had known of the family’s plan to travel, and that they had arrived in Canada on visitors’ visas. Their relatives grew concerned when messages from the family stopped coming, about a week after they had left.

Both Jagdish and Vaishaliben were working at one point as teachers, and had appeared to have a well-anchored life in India. But like many in the village of Dingucha, they felt compelled to leave, idealising a life abroad full of opportunity.

“Every child here grows with the dream of moving to a foreign country,” a Dingucha councilman told the BBC at the time.

As the Patels finalised their travel plans, Border Patrol agents an ocean away in the US had noticed a pattern of “fresh footsteps” in northern Minnesota, near the US-Canada border, that would appear each week on a Wednesday.

Suspecting that they had belonged to people crossing the border unlawfully, the agents began surveying the area regularly, including on the morning of 19 January 2022, despite the snowstorm that made the rural roads practically impassable.

It was the footprints that eventually led to police finding the Patels in snow-covered field.

“What I am about to share is going to be difficult for many people to hear,” assistant commissioner Jane MacLatchy with the Royal Canadian Mounted Police told reporters the following day, as they announced the news of the deaths.

“It is an absolute and heartbreaking tragedy.”