But those crimes had nothing to do with the charge of the Mueller investigation, i.e, Russian meddling in the 2016 election and Trump collusion with the Russians. It was a counterintelligence operation.
And Manafort was not prosecuted for these crimes until Mueller took over. The Feds had all this information and chose not to prosecute. We all know that the true target of the Manafort investigation was Trump. If Mueller had not been appointed, Manafort would be a free man today.