When Canada Border Services Agency and Calgary police descended on the city’s new arena construction site last month in a search for undocumented workers, there were immediate concerns.

The action came as reports of U.S. Immigration and Customs Enforcement agents’ raids on workplaces dominated the news.

The Oct. 15 action in Calgary saw workers lined up outside the construction site and required to show identification. Four workers without proper documentation were not permitted to return to work.

But Irene Bloemraad, a sociology professor at the University of British Columbia and a co-director of UBC’s Centre for Migration Studies, noted the involvement of the Calgary Police Service.

She said it raises questions about whether police should be doing immigration enforcement. In the United States, she said, it’s common that police departments don’t want to engage with immigration enforcement because it destroys trust with immigrant communities.