At that moment a pale-faced man - shaking so hard that witnesses said he looked ill - pulled out a revolver and shot Giuliano three times in the neck. He then stood over the body and fired four more bullets into his back before making his getaway.
The killer was Leoluca Bagarella - nervous, unconfident but nonetheless ruthless - who was emerging as a force to be reckoned with in the Corleonesi clan that was poised to take over the running of the Cosa Nostra. The Giuliano killing marked the beginning of a cold-blooded career in which Bagarella took responsibility for some of the Mafia's most vicious killings, enjoying a degree of power in the criminal underworld superseded only by his brother-in-law, the Corleonese boss Toto Riina.
The fact that he liked to shoot from behind, breaking one of the Mafia's rules of good conduct, proved no obstacle to his rise. On one occasion, he shot a policeman lighting a cigarette.
It is believed to have been Bagarella who, in 1992, organised the giant car bomb that killed the anti-Mafia judge Giovanni Falcone, his wife and three bodyguards on the motorway near Palermo airport.
According to testimony at the ongoing murder trial in Caltanissetta, Bagarella personally stood guard with a Kalashnikov rifle while his men stuffed a storm drain beneath the road with more than 500 kilos of gelignite, TNT and plastic explosive.
Other crimes attributed to the man known to his friends as Luchino include the revenge killings of businessmen and politicians involved with the Mafia - such as Salvo Lima, the Christian Democrat overlord in Sicily who outlived his usefulness as a contact with the political establishment in 1992.
Bagarella is even believed to have contemplated the murder of Giulio Andreotti, the Christian Democrat grandee who goes on trial in September for criminal collusion with the Cosa Nostra. According to informants, Bagarella only gave up because the security net around Andreotti was too tight.
But Bagarella's rise to prominence was helped considerably by the slowness of the Italian justice system and, probably, the collusion of certain sectors of the state.
He was arrested within a few months of the Giuliano killing - in circumstances very similar to those of Saturday night - but was not given a definitive life sentence until two months ago.
He spent six years in prison during the 1980s for a spate of relatively minor offences, but had to be released in 1990 because his period of preventive custody for his bigger crimes had run out.
For much of the 1990s he managed to move around with virtual impunity, throwing a huge party for his wedding to the sister of a fellow-gangster at Palermo's poshest hotel, the Villa Igiea, in April 1991. Policemen were powerless to intervene because no arrest warrant was forthcoming.
When he was finally tracked down on Saturday night, the fact that he was unarmed and alone suggested he did not feel particularly threatened.
It is not impossible that Bagarella was betrayed by rival members of the Corleonesi gang vying with him for the leadership. Candidates include Giovanni Brusca, fellow plotter of the Falcone murder, and Bernardo Provenzano, believed to the mob's financial brain.
The main issue preoccupying his interrogators will be whether he had taken over the Cosa Nostra from Riina with a similar leadership structure, or whether a new generation has taken over and left old-timers like Bagarella out in the cold.
Recently the fight against the Mafia had appeared to be in some disarray. Political turmoil in Rome and a toothless parliamentary anti-Mafia commission had, according to experts on organised crime, allowed Cosa Nostra to regroup and regain confidence - gunning down the relatives of high-profile informers as a warning to others to keep silent.
Yesterday Bagarella was being held for questioning at the headquarters of the anti-Mafia police pending his transfer to the maximum security island prison of Asinara off northern Sardinia.Reuse content