BARRIE, Ont. -- Provincial police say four people have been charged in a human trafficking investigation that freed dozens of alleged “modern-day slaves” in Barrie, Ont., earlier this year.

Investigators had announced in February that they had freed 43 people who were allegedly forced to work as cleaners at vacation properties in Ontario for as little as $50 per month.

At the time, they said criminal charges were pending, with authorities focusing on the workers' needs first.

Police said Thursday that four people were charged with offences that include trafficking in persons, employing a foreign national without authorization and possession of property obtained by crime.

They're scheduled to appear in court in Barrie on July 3.

Police say the charges relate to the accused's involvement with a company that allegedly supplied Mexican-born workers as forced labour to a number of businesses that were unaware of the employees' circumstances.