The Locked Room
by Herbert Ashton, Jr.

John Burgess is found murdered in his study.

An insurance investigator arrives and with the permission of a blustering detective, Sergeant Ryan, proves that Burgess committed suicide, only to have the medical examiner announce that Burgess was stabbed in the back.

Through Ryan's yelling and buffoonery, two members of the household confess the killing.

At the end of the first act it seems that he died by a pistol shot; in the second it is proved that a stiletto was the lethal instrument, and also that prolonged arsenic poisoning was the cause of his death.

Did he kill himself?

No one in the audience knows until twenty seconds before the final curtain.