The Charteris Mystery (Musaicum Vintage Mysteries). Dorothy Fielding

Rose Charteris' dead body at the bottom of a sand pit let the onlookers believe that probably she died due to a freak accident… But Chief Inspector Pointer is deeply suspicious as there are many people who will directly benefit from her murder! Excerpt: "Cockburn thought that the colonel looked vexed. An old scar on his forehead blazed a bar of crimson. A sign of anger. Yet he could hardly be annoyed with the girls for knowing where the professor was. But already the colonel had puzzled him on the courts. Generally a fine player—to-day! Cockburn eyed him as he cut a cigar unevenly, and decided that something was up. It was not Colonel Scarlett's habit to chip a Corona like that. Nor to hold it so tightly that it leaked. Nor to smoke it at a pace which would turn it into an overheated cabbage stalk."