Death by widow

Japanese police arrested a woman for murdering her husband.

The thing is, this wasn't her first.  Her previous five husbands and/or boyfriends all died as well.

Kakehi reportedly married at least three times and had relationships with three other men who died. All died within a few years of starting relationships with her, all in western Japan...

Other cases are still under investigation. Cyanide was also found in the blood of a 71-year-old partner who died in 2012 - a death initially attributed to heart failure. 

This is fine fodder for horror tales.  Mysteries, too.

(thanks to Todd Bryant)