Thank you for the question.
The IRCC is responsible for assessing the eligibility and admissibility of workers, students and other foreign nationals who want to travel to Canada. We do that in accordance with the legislated requirements for eligibility and admissibility. With the information that is available to us at the time, the officer assesses to ensure that they are not a threat to the security of Canada and the health of Canadians, and that they have no criminal background in terms of the information that's provided to us. After an assessment, the officer determines that the individual is not inadmissible.
In terms of the activities of the foreign national after arriving into Canada, compliance with the student permit or work permit is a responsibility of IRCC and a joint responsibility with ESDC with regard to work permits, but any other activity, criminal or otherwise, would be under the purview of our enforcement partners, such as CBSA or RCMP.