Mrs Thompson

In the short story The Red Signal, Mrs Thompson is a medium. She was invited to a dinner party at Jack and Claire Trent's, to hold a seance. During the seance she got a message from a spirit for one of the men in the room, but the spirit did not specify which one among them. The message was not to go home, because there would be blood. Not much blood, but enough.

Portrayals
In the episode The Red Signal of The Agatha Christie Hour, a TV film adaptation of the story, the part of Mrs Thompson is played by Rosalie Crutchley. There is an additional scene where after dinner she talks to Claire Trent who is upset by the seance. Mrs Thompson says she can only speak the truth but Claire tells her to get out of the house.