Officials at University of Toronto are questioning student union leaders who sheltered out of town protesters during the G20 summit.

The Graduate Student Union allowed demonstrators to stay at their union-run campus building this past weekend. They turned the gym into a makeshift hostel.

Toronto Police raided the building and took about 70 people into custody.

"We've seized bottles with unknown substances inside, we've seized black clothing, bricks, sharpened sticks, items that you definitely do not need to spend any time in Toronto," Constable Rob MacDonald said.

That’s the same type of weapons and clothing that violent protesters used in the downtown core.

With files from The Canadian Press.