On 23 May 1992, Falcone, his wife and three bodyguards were killed by a bomb planted under the highway outside of Palermo. Giovanni Brusca later claimed that 'boss of bosses' Salvatore Riina had told him that after the assassination of Falcone, there were indirect negotiations with the government. Former interior minister Nicola Mancino later said this was not true. In July 2012, Mancino was ordered to stand trial on charges of withholding evidence on 1992 talks between the Italian state and the Mafia and the killings of Falcone and Borsellino. Some prosecutors have theorized that Borsellino was killed because he had found out about the negotiations.