On one of these occasions Cassarà and Zucchetto recognized the two top killers Pino Greco and Mario Prestifilippo, but they could not arrest them because they fled.
Cassarà was a close associate of Giovanni Falcone and the so-called Antimafia pool of the Republic Prosecutor's Office of Palermo, and his investigations contributed to the groundwork of the first Maxi Trial.
On the afternoon of August 6, 1985, he was returning to his home in Viale della Croce Rossa 81 in Palermo in an Alfa Romeo Alfetta together with two escort officers.
As he walked out the escort car and reached the front door of his home, a group of hitmen armed with AK-47 rifles and Submachine guns, headed by Giuseppe Greco, Antonino Madonia and Giuseppe Giacomo Gambino, opened fire from the windows of an apartment building next to his home killing Cassarà and another officer while the second survived the ambush by hiding under the car.
Cassarà, was hit by the killers almost simultaneously with Antiochia and died inside the entrance hall in the arms of his wife Laura, who saw the ambush with their daughter from the balcony of their home.