Did she definitely do it?
If you're reading this, chances are you've either watched Killer Women, or are planning to, and know "she" refers to Amanda Lewis, a 35-year-old mother from Florida who was convicted of drowning her seven-year-old daughter Adrianna in a paddling pool in 2007.
Her conviction hinged on the testimony of one witness - her young son, AJ, who was five when he saw his mother murder his half-sister.
Lewis, who featured in part two of the ITV documentary last night, will never be released from prison in Texas. She still maintains her innocence.
The stories are macabre and fascinating, but it is Lewis' murder conviction and the controversial nature of her trial that has caused the most discussion.
Is she a woman rightly separated from society as a punishment for taking a life, or, as Morgan ponders, was the death of her daughter “just another tragic case of the most common cause of accidental child death in Florida?”
The twists and turns in the story are well-documented online, as well as in Morgan's investigation. She passed a lie detector test and her son's story changed several times during questioning.
On the other hand, Lewis' co-workers testified she had lost her temper with her daughter, whose ADHD sometimes brought about challenging behaviour, and police reported that her children's rooms were barren and smelt of urine.
She was convicted by a jury of her peers, but doubters could argue that the US is not exempt from miscarriages of justice.
Viewers who vented their reactions on Twitter had mixed opinions, with some questioning why a seven-year-old boy would tell such a lie about his mother, while others condemned the fact he was put up to testify at all:
Watching killer women, why would the little boy need lie about seeing his own sister get killed by his mother.He obviously saw what happened— Cathan12 (@UkBelieber12) May 18, 2016
Crying at killer women with piers Morgan.. Seeing that little boy cry when he noticed his mam in the court room, broke my heart— amiehill. (@amiee_hill) May 18, 2016
As we pour over cut-and-dried true crimes from behind our TV screens or newspapers, we're spectators-come-voyeurs, safe in our outrage and fascinated by such stark and diabolical aberrations from our own lives.
When we believe there's a chance the accused is innocent, everything we know to be right is turned on its head. We feel both empathy for the wronged victim and fearful that the rule of law - the very foundation of civilised society - cannot be trusted.
Despite the tantalising element of doubt in Lewis' case, this is very likely to be a perennial cliffhanger, with no satisfying EastEnders doofs, no season two. In three years time, AJ, who has been adopted, will be old enough to decide whether he wants to see his mother again - away from the glare of the world's cameras.
Watch the trailer for Killer Women