What is Chicago amnesia?

The term Chicago amnesia, born more than six decades ago, is still used by police and federal authorities all over the country to describe the reticence of witnesses in testifying against organized crime. In Chicago in the 1920s, law enforcement of?cials found it virtually impossible to prosecute gangsters because of the fear they instilled in potential witnesses. Even eyewitnesses who eagerly came for-ward on seeing a crime suddenly developed a startling loss of memory when they learned the identities of the culprits.