This docuseries (which currently has two seasons) tells the stories of 10 convicted killers each season, with every instalment focusing on a different notorious prisoner who has been sentenced to death for capital murder. You can also watch the spinoff series, I Am a Killer: Released, which revolves around Dale Wayne Sigler, a convict who was paroled 30 years after being sentenced to death for murder.
Watch I Am a Killer on Netflix.