Piers Morgan travelled across the Atlantic to meet some of America's most notorious female murderers and won praise for his sensitive approach to a difficult subject.
In the first episode of ITV's Killer Women, Good Morning Britain's Piers travelled to Texas to meet Erin Caffey.
At the age of 16, she masterminded the brutal murder of her entire family, but her father survived. Erin will remain behind bars until she is almost 60 years old for conspiring with her boyfriend to kill her mum, dad and two younger brothers.
Viewers who watched took to Twitter to express their admiration of Piers, and their shock at Erin's actions.