Women Serial and Mass Murderers (McFarland & Company)

It is at 31.4 years that the average woman multiple murderer kills the first of her 17 victims, whom she usually knows or is related to. The preferred method is poison, usually arsenic. She is more likely to prey on the vulnerable--the very young or the very old--than her mail counterpart. Her killing spree lasts five years; when caught, she shows little remorse.