In June 1982, banker Roberto Calvi's body was found hanging under Blackfriars Bridge. Blackfriars Bridge is assumed to be linked to Freemasonry. And that link is interesting since Roberto Calvi was a member of the lodge P2. He was also the banker of Banco Ambosiana which itself was linked to the Vatican. Enough material for a conspiracy theory. On top of that, his secretary was also found murdered on the same day.
City of London