In the book A Question of Intelligence, author Daniel Seligman notes that mob leader John Gotti had a tested IQ of 110.  Seligman found this figure to be quite plausible because criminals average IQ’s around 90, so an IQ of 110 was enough for Gotti to climb to the top of the crime world.  Similarly, Charles Manson had a tested IQ in the 109-121 range.  The people who killed for Manson probably had IQ’s around 90, but Manson being about 19-31 points higher, could easily manipulate them.