In this paper we discuss a case study for the UK Police IT Organisation (PITO) on using a model-based approach to verifying web service composition interactions for a coordinated service-oriented architecture. The move towards implementing web service compositions by multiple interested parties as a form of distributed system architecture promotes the ability to support 1) early verification of service implementations against design specifications and 2) that compositions are built with compatible interfaces for differing scenarios in such a collaborative environment. The approach uses finite state machine representations of web service orchestrations and distributed process interactions. The described approach is supported by an integrated tool environment for for providing verification and validation results from checking designated properties of service models.