Number of Serial Killers by Year in the U.S.
The highest growth of serial killers in the U.S. was between 1960 and 1970. That's entirely due to the American mega-project of building high-speed roads between the states everywhere.
Thanks to the new highways, serial killers could easily travel between the states, remain anonymous, and hide their victims on the ways between the states. Especially, the most favourite type of victims were hitchhiker, and with this new American development, there were way more of them than before.
Source: StaDaFa
