On July 15, 1997, fashion designer Gianni Versace was shot and killed. His alleged murderer's killings have been described in the press and by some criminologists as a "spree," while the FBI classifies him as a serial killer. So what's the difference?

For the many male serial killers you can no doubt name off the top of your head—Jeffrey Dahmer, John Wayne Gacy, Ted Bundy, Jack the Ripper—there are likely far fewer females of the genre that come to mind. Meet four female murders whose stories you won't forget.

Ted Bundy was one of the most prolific and notorious serial killers in U.S. history—he confessed to murdering at least 36 women, but some estimates put the number of victims as high as 100. But despite his infamy, many people find him to be one of the most physically attractive and charismatic murderers.

An excerpt from David Schmid's article, "Why Americans Are So Fascinated by Serial Killers," on HISTORY.com.

There are plenty of murderers who have killed more times than Ed Gein, but few have left a deeper impression on American culture. Read about him and watch a video on his life.

By the time the murderess's crimes were discovered at her burnt-out pig farm in 1908, her tally of victims had risen to at least 12, and possibly as high as 40.

Killers who leave notes at crime scenes or mail missives to police and the press take a big risk. Read stories and watch videos about eight murderers who just had to put it in writing.