Murders have been an indivisible component of humans and their sins since the dawn of age. It is said that no matter how smart a criminal is, he still leaves a faint trail that leads others to him. And yet, there have been incidents of murders where the gruesome crimes have gone unsolved, and with a faint aura of folklore, become mysteries. Here are 12 such murder mysteries that will chill your spine with their gruesome details and leave you wondering what exactly might have happened.