Death Sits on the Board — John Rhode

At his residence in  Beckenham  in  Kent  on the outskirts of  London, Sir Andrew Wiggenhall the chairman of the  board of directors  of a large firm of  ironmongers  is killed by an explosion that largely wrecks the house. Investigating officer  Superintendent  Hanslet is not convinced his death was an accident, particularly when another member of the firm's board is found dead. With the help of Priestley he sets out to solve the mysterious incidents that have left the remaining members of the board.