Stéphane Bourgoin, 67, falsely claimed that he had been trained by the FBI and that his own wife had fallen victim to a serial killer.

The French author has written more than 40 books about serial killers, appeared in documentaries and delivered training and seminars.

However, he finally admitted “amplifying” the truth to news magazine Paris Match after internet sleuths began to pick apart his prolific record.

Day later, Mr Bourgeoin confessed to Le Parisien that he was a “mythomaniac”, adding: “I am ashamed to have lied and to have concealed things.”