Complex sentence: Department of Justice officials agreed that her broadcasts were "innocuous," but when Toguri tried to return to the US, a popular uproar ensued, prompting the Federal Bureau of Investigation to renew its investigation of Toguri's wartime activities.
Split into simpler sentences: Department of Justice officials agreed that her broadcasts were "innocuous". But when Toguri tried to return to the US, a popular uproar ensued, prompting the Federal Bureau of Investigation to renew its investigation of Toguri's wartime activities.