This is incorrect. Canada discovered she had an incorrect visa to enter Canada, as she had a tourist visa and they determined she’d need a work visa - so they sent her back to the USA, where she had come from, to reapply for her Canadian visa and then re-enter - but the USA border agents, on seeing her getting rejected, questioned her about her stay in the USA and determined she had broken the terms of the visa she was in the USA under, and thus detained her.