It is not a criminal offence in Canada not to report a crime. The Criminal Code of Canada does not contain the offence of not reporting a crime. Even if a person suspects a crime to have occurred, they are under no legal obligation to report the suspected crime and thus cannot be found guilty of such an offence, as none exists.
Some professionals, such as doctors, lawyers, teachers, counsellors and social workers have duties and obligations under provincial legislation to report suspected crimes, but these are not laws covered by the Criminal Code of Canada. Under these Acts, some professionals are obligated to report suspicions or beliefs they have about the abuse or neglect of a child to the appropriate authorities. If found guilty not reporting a crime, they would be dealt with under the Act of their specific province, but not under the Criminal Code of Canada.
However, one could potentially attract criminal liability for not reporting a crime, if the failure to report in some way aids or abets in the commission of the crime. In such circumstances, a person could be liable as a party pursuant to the initial criminal offence pursuant to section 22 of the Criminal Code of Canada.