There is a short story that I'm sure I own but cannot find because my collection is too huge. I have the feeling it was only about 20 pages worth of story but I'd really like to read it again. I'd like the title of the story but also the collection it was in if possible. I can't think of any of the other stories that were collected with it.
I have the feeling I read it roughly 10 years ago and it was a fairly new publication at the time, although the work itself may have been older. The detective may have a series based around their exploits but I've never run across them myself in other works.
It involves a supernatural police detective who investigates a murder by getting a sample of the ghost of the victim, (a child maybe?), that's for sale at some kind of supernatural market.