Shawn finds himself with real psychic powers after an encounter with a fortune teller in a coffee shop. This isn't a blessing for him - he's seeing a ghost, experiencing visions of a murder when he touches certain items, and developing a terrible headache. In addition to the visions, Shawn hears the sound of a bird in his vision.
The ghost (Margie) implies that Lassiter is interested in Shawn. And Lassiter does seem concerned about Shawn, although he also hints that Shawn could be a suspect in the case.
Eventually, the information Shawn receives leads him and Lassiter to an apartment building - and the murderer.
There is a sequel to this fic - The Case of the Missing Conventioneers - recced elsewhere in this journal.
The Case of The Missing Cockatiel, by gryvon