The Fatal Pool

In ''The Fatal Pool,'' the family and friends of Colonel Gayton have gathered together at Framby Hall, and while most of the guests are at breakfast, Yvonne Bardwell is found drowned but with bruises on her shoulders indicating that she was held under the water. The mystery centers around the fact that as nearly the entire household was eating breakfast together, how could one of them have slipped away and murdered Yvonne?