Arsenic Anna : The True Story of Serial Killer Anna Marie Hahn

Anna Marie Hahn had a gambling habit.
She indulged her addiction at the horse races and bookie joints throughout Cincinnati in the 1930s. Anna wasn't very good at picking horses, losing time and again while accruing debt.
But it was an addiction had to be fed. 
She needed a scheme, a way to acquire money to keep her compulsion satisfied. 
Anna Marie Hahn was a clever woman. While walking through her neighborhood of elderly pensioners, the idea came to her like a bolt of lightning.
She would befriend these lonely and pathetic men. Cook them meals, keep them company. 
Then she would kill them for profit.