That Day the Rabbi Left Town — Harry Kemelman

The rabbi looks into a professor's death, in the New York Times�"bestselling series that's “the American equivalent of the British cozy” (Booklist).

Retired from his job at the synagogue in Barnard's Crossing, Massachusetts, Rabbi Small now teaches Judaic studies at a Boston college. Finally able to enjoy theological contemplation without the annoyance of temple politics, the rabbi is shocked when one of his colleagues is found dead in his car -- and the clues at the scene point to murder.
 
The deceased English professor was notoriously selfish and held long-standing grudges against other members of the faculty, so the list of suspects is long. But when the rabbi who took over Small's position in Barnard's Crossing is implicated, it falls to Small to clear his name and find the true killer, one last time.