A California panel denied parole for serial killer Charles Manson on April 11, 2012 and scheduled the 77-year-old's next parole hearing to take place in 15 years. Here's a look at other notorious serial killers.
John Wayne Gacy. Before the bodies of 29 young men and boys were discovered on his property in 1978, Gacy was known around Chicago for being nothing more than a friendly neighbor and Pogo the Clown. He was executed in 1994.