Maxwell's House — M.J. Trow

Two men had the job of tracing seventeen-year-old Jenny Hyde's killer. One was Chief Inspector Henry Hall, an elitist cop of the old school, who was driving in one direction only - to the top. It was his job. His territory. The other was Peter Maxwell - "Mad Max" - widower, film buff, golden-hearted cynic, and bow-tied, eccentric teacher under suspension and suspicion.
Maxwell didn't have to become involved at all. But he was so involved he didn't know how to get out. Jenny had been one of his students. Peter Maxwell was mad enough and determined to find her killer.