The first attempt at providing a concise definition of the mafia was made by Antonino Traina in his Sicilian/Italian dictionary which appeared in 1868. The mafia attracted the attention of the early sociologists and Giuseppe Alongi provided one of the most thorough analyses of the phenomenon. The law has always had extreme difficulties in defining the mafia. The term 'associazione a delinquere' was coined by the Fascist judicial authorities at the time of the antimafia campaign carried out by Prefect Cesare Mori, but it was only in 1982, with Law 646, passed in the aftermath of the killings of Carlo Alberto Dalla Chiesa and of Pio La Torre, that the fact of membership of the mafia, as distinct from activities associated with membership, become a crime in Italian law.