The Warrior's Knife. Constabulary Casefiles, #1

My name is Caelin Morrow, and I'm one of the most hated cops in the Rim Sector.  I work for a branch of the Commonwealth Constabulary, humanity's interstellar police force, called the Professional Compliance Bureau. We're the Commonwealth government's internal affairs division and hunt down bent cops, corrupt officials, and misbehaving military personnel. My fellow Constabulary members neither like nor trust me, but that's okay.
I enjoy taking out the trash. When a senior navy officer is accused of murdering an envoy from the Shrehari Empire on Aquilonia Station, a human trading post on an airless moon, everyone fears it might shatter the peace with our restive neighbor. That makes it a case for my unit because we're known by humans and Shrehari alike as the last of the incorruptibles, the ones unafraid of digging up the truth. Since I'm the chief superintendent commanding the Rim Sector PCB Detachment, I only handle extremely sensitive cases myself.
Yet this one could quickly become the trickiest of my career. The Shrehari are a touchy species and would consider a mishandled inquiry, or worse a coverup, sufficient cause to sever diplomatic links with the Commonwealth. Yet whenever I investigate a case involving the military, I always wonder if something other than one of the seven deadly sins is involved. Was the envoy's death an act of passion or an act of interstellar politics?