William Brydges was arrested, but not convicted in Canada, for the murder of Elizabeth MacLeod. His case was a Canadian precedent, and created significant controversy after the Supreme Court of Canada upheld his acquittal. He was found to have been denied access to an attorney because he was not informed of legal services available to him when he told police he could not afford a lawyer. This case had nationwide ramifications, requiring all police officers to advise a person under arrest of the availability of legal services even if they couldn't afford them.
Read more about William Brydges: Arrest, Questioning, The Trial, Appeal