The Mafia retaliated violently. In 1988, they murdered a Palermo judge and his son; three years later, a prosecutor and an anti-mafia businessman were also murdered. Salvatore Lima, a close political ally of the Mafia, was murdered for failing to reverse the convictions as promised. Falcone was killed on May 23, 1992 with 400 kg of TNT positioned under the highway near Capaci, Sicily. Borsellino was also killed by a car bomb on July 19, 1992. This led to a public outcry and a massive government crackdown, resulting in the arrest of Salvatore Riina in January 1993. More and more informants emerged. Many paid a high price for their cooperation, usually through the murder of relatives. For example, Francesco Marino Mannoia's mother, aunt, and sister were murdered.