CSIS: Canadian Security and Intelligence Service. It looks after external security, but often crosses over RCMP internal security lines. The relationship between the two is strained, at best. To the best of my knowledge, there is no such department as "Section 3."
S.Q.: Sûreté du Québec, the Quebec Provincial Police.
The francophone name Denis is pronounced den-ee.
Kingston Federal Penitentiary is Canada's foremost maximum security prison.
It is not my intention to confound the reader, but there will be a requirement to shift from one name to another for a particular individual. I hope it doesn't prove too confusing.