IIB, short for Integrated Investigation Bureau, is a fictional special unit of the RCMP located in Toronto. They specialize in cases the police don't take. Cases like companies dealing under the table, weapons dealers, intelligence leaks, etc. The IIB made its first apearance in Lady in the Lake.
The building itself houses floors of offices, with the centeral IIB force on one floor. It also has an interrogation room with a one way mirror so people can look on.