"Female serial killers are more rare than their male counterparts, but they aren�t nonexistent; about one in six serial murderers is a woman."

"As a group, they are often overlooked and underestimated," writes Emily Anthes in The New Yorker.

The details of the women�s crimes differed notably from those committed by men. Nearly all of the women in Harrison�s study had killed people whom they knew, often targeting their husbands and children. Male serial killers, in contrast, appear much more likely to kill strangers. Whereas the most common motive for male serial killers is sex, female murderers were most often driven by money....

Harrison also found that many of the killers worked in caregiving roles, as nurses, Sunday-school teachers, babysitters, or stay-at-home moms....

One reason that female serial killers garner so little attention may be their modus operandi�targeting relatives, the elderly, or the ill, and using relatively inconspicuous weapons....