Shadow on the Glass e-bog

A classic Agatha Christie short story, available individually for the first time as an ebook.When invited to Mr and Mrs Unkerton's party in Greenway's House, Mr Satterthwaite learns of a haunted window, which no matter how many times it is replaced always contains the image of a cavalier in a plumed hat. When gunshots are heard, Satterthwaite finds that two of the guests have been shot dead, which is shortly followed by a sighting of the cavalier in the newly-replaced window pane. Can Mr Quin shed light on the mystery?