Mystery at Olympia

Constable Frean had an unpleasant sensation that he was not, as he seemed to be, patrolling a respectable London suburb, but was back at the Front in the year 1918, enduring a particularly vicious bombardment. Crash! With a roar like a bursting shell the roof of a nearby house blew off. Heading a rescue party, the constable found part of the house in ruins, and the owner, Sir Andrew Wiggenhall, missing. Eventually, his remains, or part of them, were discovered in the garden. Thus passed the Chairman of the Board of Porslin Ltd.
Some months later another member of the same board of directors died in mysterious circumstances. Still another followed shortly.
The reason for these apparently unrelated mysteries puzzled the police and intrigued Dr. Priestley. After a series of clever deductions, and as a result of clues which led far back into the past, he unearthed the secret of the Death that sat on the Board of Directors.