Key moments from Lindsay Clancy's five-week trial over children's killings

Closing arguments are set to begin on Thursday in the trial of Lindsay Clancy, the Massachusetts mother charged with murdering her three small children at their home in suburban Boston.

In a case that has captivated the American public, Clancy has not disputed that she killed them, but her lawyers argue she should not be held legally responsible because she was suffering from severe mental illness.

Clancy is charged with three counts of first-degree murder in the January 2023 deaths. If convicted by a jury, she faces life in prison without parole.

Here are some of the most notable moments in the emotional five-week trial.

Arguing a calculated decision to kill - or insanity

Prosecutors allege that on 24 January 2023, Clancy intentionally strangled all of her children - Cora, 5, Dawson, 3, and Callan, eight months - with fitness bands in their Duxbury, Massachusetts, home before jumping from a second-floor window. Clancy, now 36, was paralysed by the fall and attended the trial in a wheelchair.

Lindsay Clancy's trial puts postpartum psychosis in the spotlight

Clancy's attorneys, while defending her, have never refuted her role in the killings.

Instead, they have put forth a defence of insanity, arguing that Clancy had hallucinations and delusions after giving birth to her youngest child. They pointed to treatment for mental health problems and that she checked herself into a psychiatric hospital just days before the deaths.

Prosecutors, meanwhile, have argued Clancy made a calculated decision to intentionally kill her children and should be held legally responsible. They allege that at the time, Clancy sent her husband, Patrick Clancy, out on errands so that he would not be home.

Clancy's family, including her former mother-in-law and husband, have testified about her mental state leading up to the deaths.

The five-week trial has sparked interest on social media as thousands watched the court proceedings. Hundreds of women have showed up outside the courthouse to support Clancy, wearing pink shirts with phrases like "She Needed Help" and "Peace For Lindsay".

'A really hard time': Clancy's ex-husband takes stand

Over two days, Clancy's ex-husband, Patrick, told jurors about his ex-wife's declining mental health after giving birth and described the day his children died in gruesome detail.

He told jurors that Clancy's "big spiral" began about a month before their deaths.

"She started to lose a lot of weight, and she became very depressed, and she was having a really hard time," he said.

He described her intermittently seeking help from doctors and taking a variety of medications, adding that he recalled her saying she was starting to have thoughts of suicide.

Patrick Clancy described his last image of son Dawson sitting on the couch eating chicken nuggets before he left to get food and medication. He came back to find his children dead.

Lindsay Clancy sobbed in court as a recording of her husband's 911 call played. He can be heard screaming, "She killed the kids", after finding their children in the basement.

Since the beginning of the trial, conspiracy theories about Patrick Clancy have swirled online, including some speculating about his involvement. But he was never a suspect or under suspicion by investigators; Lindsay Clancy admitted to killing her children and her attorneys have not denied that.

Battles between lawyers and experts over Clancy's care

More than 10 expert witnesses testified for both the defence and the prosecution, including some who clashed with lawyers over Clancy's mental health.

Over the course of her treatment, Clancy was put on over a dozen medications, and sought help from a suicide hotline and the emergency room.

Clancy's team tried to convince jurors she had postpartum psychosis, a rare condition in which postpartum women can experience mania, depression or a mixture of both. Clancy claims she experienced hallucinations and delusions.

One day in the courtroom grew particularly heated as one of Clancy's psychiatrists, Jennifer Tufts, testified for the prosecution that Clancy did not show signs of psychosis during their sessions.

There were "no serious signs that her safety or anyone else's safety was at risk," said Tufts, who saw Clancy over a dozen times for five months.

But defence attorneys pointed to Tufts' medical notes, describing Clancy's "not hyper, pressured speech". Pressured speech - a rapid, frantic way of talking - can be a sign of mania.

Tufts denied that she believed Clancy had pressured speech, saying the "not" applied to both the words hyper and pressured. As defence attorney Kevin Reddington pressed her, she replied: "I don't care what it says. I know what I meant."

Reddington also grew tense as he repeatedly questioned another prosecution expert, psychiatrist Avram Mack, about whether postpartum psychosis is a diagnosis.

The American Psychiatric Association views postpartum psychosis as only a proposed illness, he said.

Mack avoided calling postpartum psychosis a recognised diagnosis, at one point responding: "I'm not sure if that specifically answers your question."

In a frustrated tone, Reddington responded: "I don't care."

Clancy's mother testifies

In addition to Patrick Clancy, Lindsay's former mother-in-law, her mother and her sister also testified, telling jurors about Clancy's deteriorating mental health after the birth of her son.

Lindsay Clancy was "begging for help", her former mother-in-law Susan Clancy testified.

"She had insomnia. She was losing her appetite," she said. "She was very anxious and sad."

She added that Clancy had been a "very nurturing" mother until the birth of her youngest son.

Clancy's mother, Paula Musgrove, said her daughter told her and her ex-husband that she was having thoughts of harming the children a month before their deaths.

Musgrove said her daughter was becoming paranoid and expressed that she thought her medications were "destroying her mind".

Clancy's sister Allison Ozga told the court that her sister was experiencing suicidal thoughts every day a month before she killed her children.

Judge tells jurors to disregard testimony about Catholic faith

Two days before closing arguments, Clancy's defence team requested a mistrial after prosecutors asked witnesses about her Catholic faith.

Prosecutors last week asked Clancy's former mother-in-law, Susan Clancy, whether she was aware that murder was considered a "mortal sin" after asking her if she was Catholic, testimony that the judge asked jurors to disregard.

Then, this week, forensic psychologist Kirk Heilbrun, who interviewed Lindsay Clancy after the killings, testified that he had asked Clancy whether suicide was considered a "mortal sin" while discussing her Catholic upbringing.

Judge William Sullivan denied Clancy's legal team's request for a mistrial, but told jurors it was an "absolutely inappropriate area of testimony".

"It is to be stricken. It is not to be considered. I can't be any more clear of that," he said.

With additional reporting from Ana Faguy and Brandon Drenon

If you are suffering distress or despair and need support, you could speak to a health professional, or an organisation that offers support. Details of help available in many countries can be found at Befrienders Worldwide. www.befrienders.org.