On December 28, 1956, the Grimes sisters, 15 and 12, left home to watch heartthrob Elvis Presley in Love Me Tender in Chicago. Six decades later, their inexplicable murder remains unsolved.

For nearly two decades, Chicago faced a curious rise in the number of unsolved murders against women involving strangulation—all in certain areas of the city. We take a look at one of the unsolved cases and what police are doing to solve the string of murders.