ST. LOUIS (KMOX) - The American Civil Liberties Union has won a, case protecting the rights of Missouri prison inmates to find out if their incoming mail is being censored.

ACLU Attorney Grant Doty says this is good news from the 31,000 Missouri inmates who may never have known about the mail they didn’t get.

“What were being censored were publications people were receiving so a prisoner may seek a publication that could help them study up on the law in order to gain their freedom and maybe file a lawsuit,” Doty said.

“We know that they censor mail for security purposes and that is not what we were challenging in this case,” he added. “What we were challenging is the prison policy, statewide for all state prisoners, where they would censor the mail and they would not tell the sender the mail they were sending to the prisoners was not actually reaching them.”

In this particular case, a publishing house cried foul when nine copies of a book about Kansas City street life and prison were never delivered to nine inmates.