Diplomatic Corpse, by Phoebe Atwood Taylor (epub/Kindle/pdf)
"Buff" Orpington arrived in picturesque Quanomet to find the little Cape Cod town in ferment. A stupendous pageant of American history was being staged, and the inhabitants of Quanomet had time and thought for nothing else. But all was not as it should be in the small community. There had been more curious incidents than could be attributed to the usual petty jealousies and maneuverings for the best parts and positions. Quanomet was, in fact, in its modest way about to make history, and Buff finds himself taking an uncomfortably prominent role when he discovers a newly made corpse in the cemetery. After too long an absence, Asey Mayo, the salty Cape Cod Sherlock, returns in fine form to solve the baffling murder in his own inimitable way.