The 38-year-old Aglieri, known as "U Signurinu" (the little lord) for his relatively sophisticated education and refined manners, was taken by surprise while hiding out in a disused lemon warehouse in the dilapidated industrial area of Bagheria, east of Palermo.
A dozen police in full assault gear, who had been staking out the premises all night, hurled two volleys of stun gas before bursting into the building and slapping Aglieri in handcuffs along with two of his closest associates, Natale Gambino and Giuseppe La Mattina.
Aglieri, wanted for a string of prominent killings including those of the anti-Mafia magistrates Giovanni Falcone and Paolo Borsellino, was believed to have been rebuilding the military wing of Cosa Nostra, which has been devastated by a series of high-profile arrests over the past four years.
Aglieri is considered one of the sharpest brains in the Mafia and a man singularly talented at covering up his tracks. Although active since the early 1980s, his name was not even brought to prosecutors' attention until 1989. It took the authorities almost a year to locate him following the arrest of his right-hand man, Carlo Greco.
As late as Thursday night, the authorities were not sure of his identity and had to call on the captured Mafia killer Giovanni Brusca, a former senior colleague of Aglieri's, to confirm it.
As reported in The Independent a month ago, prosecutors in Palermo have been growing increasingly gloomy about their job because of restrictive new legislation on the justice system and an attempt to cut back the country's witness protection programme. Palermo's chief prosecutor, Giancarlo Caselli said yesterday: "We feel proud because some ill-informed people had claimed that the advent of Mafia informers had diminished our investigative abilities," he said. "Now they will have to think again."