The former husband of a Massachusetts woman accused of killing their three young children is expected to return to the witness stand Wednesday, continuing emotional testimony about the day their family's life was shattered.

Patrick Clancy has told jurors that Jan. 24, 2023, began with doctor's appointments, snowman building and arts and crafts before ending with the deaths of the couple's three children.

Prosecutors allege Lindsay Clancy, 34, strangled daughter Cora, 5, son Dawson, 3, and 8-month-old Callan after sending her husband out on errands. They say she then attempted to take her own life by jumping from a second-story window, leaving her paralyzed from the waist down.

Lindsay Clancy does not dispute that she caused her children's deaths. Instead, her defense argues she was suffering from postpartum psychosis, a rare mental illness that can develop after childbirth, and lacked criminal responsibility for her actions.

Prosecutors contend Clancy acted deliberately and should be held fully responsible.

Patrick Clancy was the trial's first witness Monday, telling jurors he watched his wife's mental health deteriorate in the months leading up to the killings.

He testified that she described experiencing intrusive thoughts about harming the children and about suicide, but said she appeared to be improving and seemed especially happy in the weeks before the deaths.

He told jurors the day of the killings had started as one of her "best days."

If convicted of murder, Lindsay Clancy faces life in prison without the possibility of parole. If jurors find she was not criminally responsible because of mental illness, she would be committed to a state psychiatric hospital instead.

The trial paused Tuesday and resumes Wednesday with Patrick Clancy expected to continue his testimony.

If you are based in the USA, and you or someone you know needs mental health assistance right now, call or text 988, or visit 988lifeline.org to access online chat from the 988 Suicide and Crisis Lifeline. This is a free, confidential crisis hotline that is available to everyone 24 hours a day, seven days a week.

If you are experiencing feelings of distress, or are struggling to cope, you can speak to the Samaritans, in confidence, on 116 123 (UK and ROI) or visit the Samaritans website to find details of your nearest branch.

If you are in another country, you can go to www.befrienders.org to find a helpline near you.