THE CORPSE SPEAKS!
Ronan O'Casey who played the 'older man' and the corpse tells the inside story of Blow-Up. It seems there really was a full blown murder plot within the movie that was cut out of the film entirely. Fascinating. Even neighbor Sarah Miles was involved in the plot. Seems Antonioni was SO over budget that he cut it all away to leave a complete blank mystery at the center of the film.
http://www.rogerebert.com/rogers-journal/corpse-from-blow-up-speaks