Mission 115 was the name given by DOI-CODI (an army repression body during the military dictatorship) to a supposed "vigilance" operation in Rio de Janeiro during a musical show at Riocentro on May 1, 1981. In fact, was a bomb attack, the final frustrated, aimed at sabotaging the country's re-democratization. For the first time one of the members of that team of terrorists, former police officer Claudio Guerra, tells in detail how the operation was planned and executed. The recent work of the National Truth Commission also sheds new light on the episode and its successive attempts at scrutiny over more than three decades.