Albert Einstein Einstein did not return to Germany. He settled in the United States and became an American citizen in 1940. On the eve of World War II, he endorsed a letter to President Franklin D. Roosevelt alerting him to the potential development of "extremely powerful bombs of a new type" and recommending that the US begin similar research. This eventually led to the Manhattan Project. Einstein supported the Allies, but he generally denounced the idea of using nuclear fission as a weapon. He signed the Russell–Einstein Manifesto with British philosopher Bertrand Russell, which highlighted the danger of nuclear weapons. He was
Murder of the family of Robert Einstein early 2010s in both Germany and Italy to identify them. The events were also the subject of a German documentary featuring Einstein's nieces who witnessed the events in 1944. Robert Einstein was born in 1884 in Munich, the son of Jakob Abraham Einstein. Robert was a cousin of Nobel Prize Laureate Albert Einstein, as Hermann Einstein, Albert's father, was an older brother and business partner of Jakob Einstein, who persuaded his older brother to move their families and factory to Pavia, Italy. In 1944, Robert Einstein, who had lived in Italy for many decades, resided with his family in Rignano