This hinges on the postpartum psychosis defence – her legal team argued that Clancy hallucinated a voice after giving birth to her youngest child that told her to kill the children.

Expert witnesses told the court how severe this illness can be, and family members testified about Clancy’s state of mind.

Under Massachusetts law, there is no burden on Clancy to prove her mental illness and that she lacked criminal responsibility.

Rather, it is on the prosecution to prove beyond reasonable doubt that she was criminally responsible when she killed her children, criminal defence lawyer Elyse Hershon told the BBC.

They can do this by either proving beyond reasonable doubt that she didn’t suffer from a mental illness at the time or that, while she had a mental illness, she still controlled her actions and knew they were wrong.

A not guilty verdict would mean Clancy went free but that is considered highly unlikely. Much more likely is a not guilty by reason of insanity, which would result in Clancy being detained at a hospital.

“The case really comes down to where she is going to serve the rest of her life; the defence thinks it should be a psychiatric facility, the prosecution thinks it should be in a state prison,” Hershon said.