What key events have occurred before the start of the play? Why do you suppose these events are not presented in the play itself?

The key events occuring before the start of the play include Jogn Wright's murder, and his wife's arrest for the crime. The events themselves preclude the plot and are responsible for the play's action. The murder itself unimportant.... it is the understamding of the murder that takes center stage, which is the reason the action takes place in the farmhouse rather than the police station, and why it is centered in the kitchen rather than the bedroom (the crime scene).