>In 1950, the FBI opened a file on Malcolm after he wrote a letter from prison to President Harry S. Truman expressing opposition to the Korean War and declaring himself a communist.[55] That year, he also began signing his name "Malcolm X".[56] Muhammad instructed his followers to leave their family names behind when they joined the Nation of Islam and use "X" instead. When the time was right, after they had proven their sincerity, he said, he would reveal the Muslim's "original name".[57] In his autobiography, Malcolm X explained that the "X" symbolized the true African family name that he could never know. "For me, my 'X' replaced the white slavemaster name of 'Little' which some blue-eyed devil named Little had imposed upon my paternal forebears."[58]