Portrait of injustice: seldom seen for decades, a stark image of two of the wrongfully accused "Scottsboro Boys" comes to light.(AROUND THE MALL: SCENES AND SIGHTINGS FROM THE SMITHSONIAN MUSEUMS AND BEYOND)

The criminal case with the largest number of trials, retrials, convictions and reversals in American history started in Scottsboro, Alabama, during the throes of the Great Depression. Nine teenagers, who came to be known as the Scottsboro Boys, would spend a collective 130 years behind bars for crimes that never happened. Over the years, the case would outrage people worldwide, including artists such as Langston Hughes, who in 1932 published Scottsboro Limited, a book of four poems and a play, to raise money for the defense fund.

Now a previously unknown Scottsboro artwork has surfaced. When the pastel drawing of two defendants, by Aaron Douglas, a leading Harlem …