Beginning in World War I , German Americans were sometimes accused of having political allegiances to Germany , and thus not to the United States . The Justice Department attempted to prepare a list of all German aliens , counting approximately 480,000 of them , more than 4,000 of whom were imprisoned in 1917 – 18 . The allegations included spying for Germany , or endorsing the German war effort . Thousands were forced to buy war bonds to show their loyalty . The Red Cross barred individuals with German last names from joining in fear of sabotage . One person was killed by a mob ; in Collinsville , Illinois , German-born Robert Prager was dragged from jail as a suspected spy and lynched . Questions of German American loyalty increased due to events like the German bombing of Black Tom island and the U.S. entering World War I , many German Americans were arrested for refusing allegiance to the U.S. War hysteria led to the removal of German names in public , names of things such as streets , and businesses . Schools also began to eliminate or discourage the teaching of the German language . Years later during the Second World War , German Americans were once again the victims of war hysteria discrimination . Following its entry into the Second World War , the US Government interned at least 11,000 American citizens of German ancestry . The last to be released , a German-American , remained imprisoned until 1948 at Ellis Island , three and a half years after the cessation of hostilities against Germany
bombing of Black Tom island
Black Tom explosion
Racism in the United States