In the Dark by Brian Freeman
What a great book! This is the 4th book in the Jonathan Stride series, and it's awesome.
Jonathan is pulled into an investigation of his late wife's sister's murder when her friend comes to town with plans to write a book about the murder that took place in 1977.
Mr. Freeman does a fantastic job tying the past to the present, and even bringing in a current-day investigation that ties into the murder.