( CNN ) -- The father of Bradley Manning , the soldier responsible for the largest leak of classified information in U.S. history , says he believes his son did n't do it . He does n't see how he could have done it , Brian Manning told CNN 's Anderson Cooper 360 in an interview that aired Tuesday night . `` Logistically , I ca n't understand -- because knowing computers as well as I do -- how you could get that much data out of a room with three other people in there , you know , sitting in close proximity , where everybody could see what everybody was doing , '' he said . `` I ca n't understand how that could be done . '' His son , a former Army intelligence analyst , was convicted last month of stealing and sending a trove of classified data to the website WikiLeaks . What 's next for Bradley Manning ? He was acquitted of the most serious charge he faced , aiding the enemy , which could have put Manning in prison for life without the possibility of parole . Now , he faces a maximum possible sentence of 90 years . When he entered guilty pleas on the lesser charges this year , Manning spent more than an hour in court reading a statement about why he had leaked the information . He said that the information he distributed `` upset '' or `` disturbed '' him , but none of it , he thought , would harm the United States if it became public . `` I believed that if the general public , especially the American public , had access to the information ... it could spark a domestic debate on the role of the military and our foreign policy in general as it related to Iraq and Afghanistan , '' Manning said , according to a statement from his lawyer . Is the Snowden case Manning , Part Two ? Asked about those comments , Brian Manning said that he thought his son was posturing . `` Yeah , I think he was grandstanding , '' he told CNN , adding that if his son was , in fact , responsible for the leak , he had no excuse for his actions . `` I mean , I ca n't fathom any reason to myself why he should be -- that I should forgive him for doing something like that because it 's against my creed , or code of honor , '' he said . Brian Manning alluded to his time in the military , saying that he never spoke about what he did and wished his son had the same character . Authorities say the younger Manning delivered three-quarters of a million pages of classified documents and videos to the secret-sharing site WikiLeaks , which never confirmed the soldier was the source of its information . The material covered numerous aspects of U.S. military strategy in Iraq , gave what some called a ground view of events in the Afghanistan war and revealed the inner workings of U.S. State Department diplomacy in leaked cables . `` It 's my country as well , and leaking information that 's going to damage my country , and the soldiers in our military , you know , that would be very upsetting , '' Brian Manning said . Opinion : Manning verdict 's lesson in a digital age . CNN 's Chelsea J. Carter , Ashley Fantz and Larry Shaughnessy contributed to this report . Watch Anderson Cooper 360° weeknights 10pm ET . For the latest from AC360° click here .
Brian Manning says he believes his son is innocent . The younger Manning was convicted in the largest leak in U.S. history . `` Logistically , I ca n't understand '' how Bradley got data out , says Brian Manning .