PALERMO, Italy (Reuters) - A mafia boss was gunned down while riding his bicycle in Sicily on Monday, judicial sources said, in what appeared to have been the sort of mob killing that has become rarer in recent years as dangerous figures have been locked up.

Giuseppe Dainotti, 67, had served more than two decades in jail for murder and robbery, as a member of the Cosa Nostra mafia, before being released in 2014.

Investigators believe at least two hit men, probably on a motorbike, approached Dainetti and shot him in the neck, a few hundred meters from the scene of another mafia murder in 2014.

He was killed the day before the 25th anniversary of the killing of top anti-mafia prosecutor Giovanni Falcone, whose car was blown up by a half-ton bomb on a motorway outside Palermo.

Palermo chief prosecutor Francesco Lo Voi said the fact that Dainotti was killed in broad daylight in the center of town so near the anniversary of Falcone’s murder was symbolic.

“When anyone says the mafia doesn’t exist any more, something happens to show that it does; it comes back shooting conspicuously,” Lo Voi told reporters in Rome.

Cosa Nostra’s clout has weakened markedly since a “maxi-trial” initiated by Falcone and colleague Paolo Borsellino in the late 1980s indicted hundreds, and mafia groups on Italy’s mainland have since taken the lion’s share of the drug trade. Borsellino was killed by a car bomb two months after Falcone.

But Palermo police commissioner Renato Cortese expressed concern 10 days ago that a number of convicted mafiosi were due to be let out of jail.

“There is always the fear that if Cosa Nostra can find a rational head that can bring together the disparate souls, it could become as dangerous as it used to be,” Cortese said.

Aside from the murder of Giuseppe Di Giacomo, brother of incarcerated boss Giovanni Di Giacomo, in the same neighborhood three years ago, the number of mafia killings in Palermo has plunged in recent years.