Diana was widely believed to be one of responsible for the murder of Paride Salzillo, a nephew of the Casalesi boss.

[1] He played a key role in the Casalesi's war against the Nuova Camorra Organizzata, participating in the infamous, the Pagano Mennillo-Orsi-Gagliardi murders, in which Casalesi members positioned a machine gun on a hill in Ponte Annicchino and opened fire, killing four Cutoliani in Casal di Principe on 22 April 1989.

Shortly after being released, he was sent by the Italian government on an internal exile to Modena, where he organized a tour of extortion in Emilia-Romagna, where he was again arrested in Operation Zues.

[2] He was sentenced to life imprisonment in absentia along with fugitive Casalesi bosses Antonio Iovine and Michele Zagaria at the culmination of the ten-year-long Spartacus Maxi-Trial on 19 June 2008.

Diana's arrest was believed by law enforcement to have delivered a huge blow to the Casalesi.