Unsolved Mysteries

One unsolved mystery that I think most people know and find interesting is the Zodiac Killer. The Zodiac was a nickname given to himself. He was active in the late 1960's but continued to send in letters and ciphers into the early 1970's. Another is Jack the Ripper, he was in London in 1888. He got his name from a letter he sent to the newspaper. These are similar in that they sent messages into the newspaper and that there were suspects in each case but there was never enough evidence to arrest anyone.