In the past 30 years Garzón has led the most important investigations in Spain: Against drug cartels, against terrorist groups (ETA), and against corruption. He's also famous for his attempt to extradite Chilean dictator Pinochet to Spain to judge him for crimes against humanity.
In his last investigation Garzón ordered in-prison conversations between corrupt politicians and their lawyers to be monitored. This is legal in Spain if the goal is to prevent further crimes to be committed (such as the inmate telling his lawyer to destroy evidence, or offshore funds). This caused Garzón to be disbarred as a judge. The president of the Supreme Court that signed this disbarment (Carlos Dívar) has later on made to resign, after it was discovered that he used taxpayers money for deluxe vacations.