But security forces in the Sicilian capital are now so fearful for the prosecutor's safety that even moving him to the relative safety of Milan has been considered too risky, despite the armoured vehicle prepared for him.
Instead, the father-of-two, 51, is virtually under lock and key himself; everywhere he goes, a ring of carabinieri with submachine guns fan out around him. He is no longer able to go swimming. Jogging takes place in military barracks, always surrounded by the ring of armed guards.
Asked by La Repubblica newspaper if it felt like 1992 all over again, he said: "No, there's an important difference: there was only silence around Paolo [Borsellino]; today there are many Italians standing with us, even if certain institutions are deafeningly quiet."
His dig was thought to be at the Justice Department, which has yet to comment or act on the threats.
The failure of the state to protect his murdered predecessors - and even the strong suspicion it colluded with the Mafia killers, particularly in the case of Borsellino's murder - has preoccupied Italy for two decades.
But this time there are signs the Italian state will not bow to Mafia threats. Interior Minister Angelino Alfano has said he is ready to make the feared solitary confinement regime for jailed Mafia bosses even tougher.
It was widespread use of this prison measure against mobsters that provoked the then Cosa Nostra leader Riina to launch the bombing campaign that killed 20 people including Falcone and Borsellino in 1992-1993. And this violence led to secret talks between the state and the Mafia.
"Mafia bosses should know," Alfano told the national anti-Mafia commission, "that if they seek to send orders from inside prison, the state will not hesitate to stop them and is ready to toughen the law."
Veteran Mafia writer Attilio Bolzoni hailed Alfano's decisive response. "The Interior Minister is aware of the serious risk that currently exists in Palermo. This is a positive message because the state cannot leave magistrates by themselves."
But he said Alfano's promise to hit Cosa Nostra hard if more threats - or worse - materialised, was not itself sufficient. "The danger to Di Matteo comes not only from the Mafia but from other sources," he said, referring to "accomplices" in the bomb attacks, who are thought to have included senior security officials and even politicians.
Di Matteo is involved in a trial and related probes into the presumed talks between the Mafia and state officials in 1992, which saw many senior mobsters released from solitary confinement. Former Interior Minister Nicola Mancino is among those on trial.
"Di Matteo has not stopped this. And I think this is the real reason for the threats," said Bolzoni.
This view is shared by Di Matteo.
"Let's just say it's a coincidence," he said ironically. "The order for my death and the anonymous threats arrive all at the same time when the accused are indicted and I with my colleagues have decided not to stop the investigation."
The person who aired most of Riina's threats, jailed mobster Alberto Lorusso, has been transferred to another prison. Palermo prosecutors believe he may have been planted with Riina to learn his plans.
The prosecutor, meanwhile, has considered the personal risk he is taking. "Sometimes I ask myself if it's right to go on, for me and my family," he told La Repubblica.
"Rationally I think it's not worth it, but then a combination of feelings hits me and produces just one response: it is worth it and it is right."
- Independent