Are you ready for a riddle?

Because many years earlier he had been convicted of her murder in the absence of a body (she had run away and hidden in South America) and sentenced to a long term of imprisonment which he has served in full. Now in front of many people he is seen to kill his wife, who has returned. The 'Double Jeopardy' Rule will apply as he cannot be tried and sentenced for the same crime. He could be arrested for some sort of civil order offence - frightening old men on the street.