7-9 The Derby Poisoner, 1870s Lady Murder. 

What is serial killing and how do you define a serial killer?  The FBI says  The unlawful killing of two or more victims by the same offender(s), in separate events. 

Wife and mother Lydia Sherman (aka) The Derby Poisoner, killed for 9 years between 1863-1871.  Why did she do it? Why did it take so long to catcher her?  Scott has some of the answers and a few more questions. Listen to find out more.

https://anchor.fm/felonfile/episodes/7-10-The-Derby-Poisoner--1870s-Lady-Murder-e1c5h7j