The Almost Perfect Murder by Dee Coffeen

After twenty-five years, Detective Sargent Rob Sanchove is retiring, when unfortunately the death of an 18-year-old University of Texas student is dropped on his desk. He needs to clear this case quickly so the Lieutenant will get off his back and he can get on with his retirement. Interviews with classmates identify potential suspects but they all have airtight alibis. The coroner doesn't provide any clues and the forensics are negative as well. It's a open and shut case, or is it? A series of strange things happen which makes them wonder.