Anti-mafia activist Maria Falcone, the sister of assassinated Italian magistrate Giovanni Falcone, has become an honorary member of civil society group Repubblika.

She will be addressing a vigil being organised by Repubblika in Valletta on Sunday at 6.30pm to commemorate the fifth anniversary of Daphne Caruana Galizia’s assassination.

The group said on Sunday that at the suggestion of its president Robert Aquilina, its committee bestowed the title on Falcone, who accepted it.

Giovanni Falcone was killed by the Sicilian mafia in May 1992 with a bomb so powerful it was registered by experts monitoring volcanic tremors from Etna on the other side of the island.

The explosion, which ripped through a stretch of motorway near Palermo, had sent shockwaves across Italy, but also signalled the start of the mafia's decline.

Anti-mafia prosecuting magistrate Falcone, his wife, and three members of his police escort were killed.

A relationship between Repubblika and the Falcone Foundation has been built in recent months.