The chairman of the Massachusetts Republican Party has laid out a stinging indictment of Elizabeth Warren, saying Senator Scott Brown’s projected Democratic opponent in this fall’s election appears to have perpetrated academic fraud on Harvard University. Robert Maginn, in a letter to Harvard President Drew Gilpin Faust, said Warren may have deceived the school where she teaches law by unjustly claiming Native American heritage. He demanded an investigation. A genealogist has outlined a connection that would leave her 1/32 Native American.