Security agency services taxable: liability attaches to any person as recipient and includes investigation and security personnel provision. Services by a security agency-including provision of security personnel and investigation, detection or verification services-are taxable as taxable services. The definition of security agency covers persons rendering security-related services for property or persons. The provider is a security-agency commercial concern; the receiver rule broadens to any person. A central circular supersedes prior technical clarifications on scope, classification, valuation, export/import of services, and exemptions, and serves as the authoritative administrative guidance.