There is a rather chilling episode at the end of the third act of Julius Caesar. Mark Antony has delivered his famous oration ('friends, Romans, countrymen') and roused the mob to fury over Caesar's assassination.
They find a passer-by who has the same name as one of the conspirators. He explains he is not a conspirator, but a poet. 'Tear him for his bad verses,' shouts the mob, and kills him anyway.
As so often in Shakespeare, profound insights into human behaviour are encapsulated in brief episodes and squeezed into small corners of a crowded canvas.
This is the way in which masses of people behave when swept along by waves of anger and regret. They feel the need to punish someone. Once a suitable candidate has been identified, he is for it. If the facts inconveniently refute the theory that he is to blame, then he is punished for something else.
If an example closer to home is required, then it was supplied last weekend by the reader who wrote in to protest at my temerity in maintaining that the Princess of Wales was not assassinated by a posse of photographers.
Just as I had predicted, the initial position that 'the photographers killed her' was transforming itself gradually into 'the photographers should be blamed because they had hounded her in the past', which is emotionally satisfying but not very logical.