"When we had established the facts, we conducted the arrests," Hyland told reporters.
Hyland said while the women had some "controlled freedom," police were still working to establish what sort of conditions they lived under for the past 30 years.
"For much of it, they would have been kept on the premises," Hyland said.
He said his unit, which deals with many cases of servitude and forced labor, had seen previous cases of people held for up to ten years.
"But we've never seen anything of this magnitude before," he said.
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