Rome, May 9 - The Senate Speaker on Thursday said much needed to be done to ensure that the whole truth be revealed behind Italy's decades of political violence and terrorism. "Remembering is not enough," said Pietro Grasso on Victims of Terrorism Memorial Day. "We must have the iron will to know the entire truth, even that which has remained hidden, and to understand why it has not been possible to fully shine light on the massacres". Left- and right-wing extremist violence known as the 'years of lead' marked the 1970s and 1980s in Italy, including the kidnapping and murder of former Italian premier Aldo Moro in on this day in 1978 by members of the Marxist-Leninist Red Brigades (BR). Earlier in the day Grasso, along with House Speaker Laura Boldrini and President Giorgio Napolitano, laid a wreath in Rome's via Caetani, where Moro's bullet-ridden body was discovered in the trunk of a car. Since his death, theories have been rife on the possibility of the terrorists being infiltrated and manipulated by politicians and secret services working to keep the Italian Communist Party out of power and take revenge for Moro's overtures to them. The full complement and identities of all the terrorists who took part in the attack on Moro have never been satisfactorily established. It has also been frequently suggested that security forces did not do enough to free Moro, and that the BR was 'used' to assassinate him. The last probe into his kidnapping was shelved in 2008. "As a political representative, I feel responsible for our judicial system that has failed to find the truth in time to bring about justice," said Grasso. "The truth is now known and the murderers have confessed. Never again shall justice be denied". Details surrounding many other violent incidents in the period remain unknown. The president said Italy's ability to overcome the years of lead proves the country is capable of solving its current economic crisis and political divisions, marked by a left-right coalition government that was forged after two months of political stalemate following February's inconclusive elections. "Italy has overcome not just moments of tension but tragic periods as well that exposed it to extreme risk," he said. "If we could overcome those moments, we can overcome the current challenges".