<h1>Investigation and security services classification clarifies GST service scope and exclusions for correct code assignment.</h1> Investigation and security services are classified under a specific Service Code group for GST, listing distinct service types-investigation, security consulting, security systems, armoured car services, guard services, guard dog training, polygraph and fingerprinting services-and specifying inclusion and exclusion criteria with cross-references to alternate codes to guide correct classification and GST scheduling.