There was a group of five guys who went out in their small whaling boat in Hawaii to fish in 1979. There was a storm, and they never came back. Ten years later, their boat was found on the shore of a small island in the Marshall Islands with a shallow grave that someone made.
With the advent of advanced forensic sciences, and with news being constantly disseminated via television and Internet, very few crimes produce more questions than answers. This is why we are still mystified and intrigued by crimes that seem unsolvable, even in the age of surveillance cameras and DNA databases.