Professor Peter Plum

Throughout his school days the Professor had always admired the daughter of his headmaster from afar.
But then his "best friend" had stolen her from under his nose.

Did Dr. Black's remarrying rub salt in the wounds and cause the Professor to seek revenge?

Here are some of the questions that Inspector Grey has asked Prof. Plum. Try to read as few as possible before making your guess (by clicking on the "Murder Cards" icon above).