#8 The Zodiac Killer
Since the 1960s, the police department in San Francisco has questioned 2,500 suspects to find the real Zodiac Killer.
He murdered seven people and sent threatening and taunting letters to the press and the police.
Even though it has been over forty years since this killer contacted any authority, the search is still on for the man who sent chills down the spine of people in San Francisco for decades.
Is he still out there? No one knows!