It was FDR who first employed wiretapping. The practice continued under the subsequent Truman Administration, as well as coverups like the manipulation of grand juries. The first example occurred during the Amerasia Spy Case. In 1947, there was obstruction of justice of the grand jury hearing the case of around 40 Soviet agents that were on the federal payroll. The grand jury manipulation by the Truman Administration resulted in all the agents being freed.