On a rainy summer evening, Canadian federal police entered a social club in the city of Windsor and arrested bartender Michele Iannetta. Bewildered, he and others were rounded up and brought down to the local armoury.

The police then descended on Ianetta’s house, where his wife, Antonia, and son, Guido, watched, frozen with fear, as officers rifled through the family’s belongings for evidence of his political sympathies

A naturalized Canadian citizen whose two brothers were serving in the Canadian military, Michele did not return home that night or the next; he was eventually released four years later. He was never accused of any crime.

“When something like that like happens, your neighbours look through curtains at what’s going on. There was a great deal of shame involved,” said Susan Iannetta, Michele’s granddaughter.

The prime minister, Justin Trudeau, recently reopened bitter memories for Italian Canadians with a promise to formally apologize for what many consider a longstanding injustice: the detention and internment of hundreds of Italian Canadians during the second world war.

“We have to face the dark chapter in our country’s history … Italian Canadians have lived with these memories for many years and deserve closure,” he told reporters. “It was a time when their patriotism was questioned and their lives thrown into chaos.”

For decades, the Italian community has called on the government to recognize that it acted improperly when it detained hundreds of Italian Canadians, some of whom were Canadian citizens.

Canada passed the War Measures Act in June 1940 after Italy declared war on the UK. The statute gave the government wide latitude to carry out surveillance on the estimated 31,000 Italians deemed “enemy aliens” in Canada, as fears of fascist sympathizers took hold.

A portrait of the Iannetta family in Windsor, Ontario, circa 1938. Left to right: Guido, Tony, Louis, Antonia Troia and Michele Iannetta. Photograph: Courtesy Iannetta-Latessa Heritage/Italian Canadians as Enemy Aliens

Police quickly cast a wide net: compiling lists of Italian men who were part of known fascist organizations – but also those whose only affiliations were to Italian social clubs.

“There likely were some fascists with Italian passports in Canada,” said Raymond Culos, author of Injustice Served, a history of the internment. “The ones that really suffered where those who were just decent Italians living in Canada without any ulterior motive. But in 1940, the allies did not know what the future held.”

In total, 634 men were picked up by the police. The average time in detention was 15 months, said Culos.

Thousands more were forced to undergo a monthly registration process, checking in with the federal police to verify their address, said Culos. “In the words of one of the people I interviewed: ‘I was mortified.’ This woman she felt she was a Canadian and had been all her life.”

Michele was eventually shuttled to Camp Petawawa in Ontario, and later to the city of Fredericton, where most of the men were held. He was unable to see his wife and three children for years – first because of restrictions, and later because of the cost.

It was devastating for them … For my father, it really wore on him Susan Iannetta

“It was devastating for them … For my father, it really wore on him. How does he protect his mother? Where’s his father? When’s he coming home?” said Susan, who has read correspondence between her grandfather and grandmother. “You [could] sense the desperation.”

Michele only began speaking about his experiences in the camp in the two years before he died in 1973, said Susan.

The internment of Italian Canadians came nowhere near the scope of Japanese Canadian detention, in which the entire population of residents – many of whom were Canadian citizens – were rounded up and sent to detention camps.

But Canada apologized to Japanese Canadians in 1988 – and provided redress for internment and the seizure of private property – while successive governments have resisted formally apologizing for Italian internment, partly due to fears of liability.

In 1990, the then prime minister, Brian Mulroney, offered a “full and unqualified apology for the wrongs done to our fellow Canadians of Italian origin”, but not in parliament. Trudeau’s government says it intends to issue a former apology in parliament, but has not offered a firm timeline.

None of the people detained were ever charged with a crime, nor were they given access to a lawyer, said Culos. “Canadians of Italian origin, whose fathers and grandfathers were among those who were incarcerated, could be quite upset. Mr Trudeau’s statement will ease the pain for them, and I think they’re deserving enough of that kind of relief.”

Susan Iannetta questioned the aim – and timing – of the apology.

“It’s too late,” she said. “You can’t wipe away the shame. You can’t, you can’t do any of that. You can’t give them their lives back. You can’t make it right,” she said.

Instead, she would rather the government work to educate the public about the legacy of internment. Years on, she still remembers feeling ashamed of her identity, and seeing neighbours change their names to sound less Italian.

“I wouldn’t want anyone coming to this country to ever feel shamed for who they are,” she said.