CBS News has learned that the surveillance on Manafort occurred during the 2016 presidential campaign. According to a former U.S. official, the intercepts picked up conversations between Manafort and Russian individuals about the campaign. The intercepts potentially include conversations between Manafort and President Trump. The recordings are now part of special counsel Robert Mueller's investigation, which appears to be intensely focused on Manafort. Peter Zeidenberg, a former federal prosecutor, told CBS News he would characterize what is happening with Manafort as "very aggressive."