Priestley deliberately makes Eric a peripheral character for much of Acts I and II:
His repeated absences from the stage are used to delay Eric’s confession until the dramatic final act
Priestley deftly creates tension through a variety of methods:
The use of silence and pauses
Information about Eva and each of the character’s involvement with her is only gradually revealed to the audience
The use of photographs is used to great effect:
This assumes great importance at the end of the play when it is suspected he may have been showing a different photo to each character