In February 1992, Di Pietro began investigating Milan's politicians and business leaders for corruption and kickbacks. Together with other well-known magistrates such as Francesco Saverio Borrelli, Ilda Boccassini, Gherardo Colombo, and Piercamillo Davigo, he worked on the Mani Pulite ("Clean Hands") team, which investigated political corruption. As part of this team, he investigated hundreds of local and national politicians, all the way up to the most important national political figures, including Bettino Craxi. The Italian press named the investigation "Tangentopoli" ("Bribesville").