Arkansas billboard asks who lynched WWI veteran

This billboard can be seen from Interstate 55 in Arkansas.

(CNN)A billboard that can be seen from an Arkansas interstate is aimed at solving a cold case from 1954.

"Who lynched Isadore Banks?" the billboard asks. Isadore Banks was an African-American World War I veteran who was chained to a tree, doused in gasoline and burned beyond recognition in June 1954. The slaying remains one of the nation's oldest unsolved civil rights cases.
Below the question is a phone number on the billboard. When you call the number, you're greeted by a message with a brief explanation on who Banks was. It turns out, the billboard was put up by a group of journalists who are hoping to learn more information about the 65-year-old crime.

Who was Isadore Banks?

    Banks was a pillar in the African-American community. He joined the Army at 22, in the final months of World War I. It's not clear from his military records whether he deployed overseas. He was given an honorable discharge on August 2, 1919. In 2010, 90 years after he served and 56 years after his death, he received military honors.
    After he returned from the Army in the 1920s, he helped to bring electricity to the Arkansas town of Marion. He later became one of the wealthiest black landowners in a region with a long history of racial violence. At one point, he owned as many as 1,000 acres, according to newspaper accounts.

    What do we know about his slaying?

    There are three theories that locals have repeated since Banks' killing on why people went after him in 1954:
    -- He had beaten up a white man who had courted his oldest daughter, Muriel.
    -- White men had made several offers on his land, but he refused to sell.
    -- Banks was involved with a white woman who rented her land to him, and white people were upset.
    The FBI and Crittenden County officials say they investigated the crime, but there has never been justice for Banks.
      "Until we know who the culprits were who took dad's life and until we know what happened to our land, it can never be a complete closure," Jim Banks, Banks son, told CNN in 2010.
      The billboard, on I-55 near Marion, seems to be doing its job of shedding light on a case many people know nothing about. One driver told CNN affiliate WREG that seeing the billboard led her to looking up who Banks was. She was surprised to learn it was such an old case.