Death in the Stocks by Georgette Heyer

Beneath a sky the colour of sapphires and the sinister moonlight, a gentleman in evening dress is discovered slumped in the stocks on the village green - he is dead. Superintendent Hannasyde's consummate powers of detection and solicitor Giles Carrington's amateur sleuthing are tested to their limits as they grapple with the Vereker family - a group of outrageously eccentric and corrupt suspects