BOSTON — Prosecutors trying Lindsay Clancy for murder called a psychologist to the stand Monday who argued that the Duxbury mom was “suffering” from a severe mental illness when she killed her children but likely wasn’t psychotic.

In a dramatic turn near the end of the day, the defense moved unsuccessfully for a mistrial based on some of Dr. Kirk Heilbrun’s testimony on Clancy’s Catholic faith.

Clancy is on trial for killing her children, Cora, 5, Dawson, 3, and Callan, eight months, Jan. 24, 2023. After strangling the kids, she tried to kill herself and is now paralyzed from a fall out of her second-story bedroom window.

The defendant doesn’t dispute that she killed her children. Instead, her attorney Kevin Reddington is arguing that Clancy was suffering from postpartum psychosis – that she heard a voice that commanded her to kill the kids then kill herself.

But Heilbrun said that Clancy never reported having auditory hallucinations, a sign of psychosis, before that night in 2023 or after.

“To put it mildly, that would be a very, very unusual pattern or manifestation of how this kind of thing comes about,” he testified.

Heilbrun, a rebuttal witness for the Commonwealth, said that he has testified in more than 300 cases during his career and that about three quarters of the time, it has been for the defense.

The forensic psychologist told jurors that he only met with Clancy over the course of three days last April, and conceded that that can shape some of the testing he performed. In addition to the interview with the defendant, Heilbrun said he pored through her medical records, police reports, and spoke with her ex-husband and ex-mother-in-law, Patrick and Susan Clancy.

Heilbrun described Clancy’s decline during the fall of 2022 into January 2023.

In the month before she killed the children, Heilbrun said Clancy “was in pain, she was suffering, she was doing a little bit better than she had before she went into Mclean” on New Years.

He diagnosed her with bipolar ii, a less severe form of bipolar disorder. He also noted that Clancy was suicidal then and continues to be so now.

Heilbrun described the intrusive thoughts of harming herself and her kids that had started in December 2022.

“The way she described these, they were not auditory hallucinations, they were her own thoughts,” Heilbrun said.

As for the night of the killings, Heilbrun said he considered two different possibilities.

According to Heilbrun, there was more evidence for the latter.

She reported 18 or so minutes of psychosis, during which she heard a male voice commanding her to kill her children then herself, a situation that seemed unlikely to Heilbrun in part because it is the only time she’s ever reported those symptoms.

“It’s appealing as an explanation because it could explain acts that seem so out of character for her,” Heilbrun said.

However, the psychologist said that it appeared that the voice was more likely her own thoughts born from her suffering and depression that she reported before the killings.

Heilbrun brought up how Clancy said she’d told her children, “Go to God,” as she strangled them, saying this was evidence that this was suicide combined with altruistic filicide, or a killing born of love rather than hate or greed.

She expected when they all died, then they would be together in heaven, he said.

Heilburn mentioned asking Clancy how she would have believed that she, too, could have gone to heaven, considering that the defendant grew up Catholic, and the Catholic Church considers suicide a mortal sin.

Reddington instantly objected. Judge William Sullivan brought the parties to side bar and then called a brief recess.

When court was back in session, the jury wasn’t brought back in.

“This has obviously been a long trial,” Reddington said, “I have to move for a mistrial, reluctantly.”

He said that Catholic faith and the concept of mortal sin had been injected into the proceedings.

“The fact that this is not the first time that this has happened during the trial,” Reddington said. “I believe it was intentional misconduct.”

Assistant District Attorney Jennifer Sprauge argued that the questions she’d posed to the witness had not been about religion and that she believed Heilbrun had made an honest mistake.

Sullivan said that he would not declare a mistrial, instead telling the prosecution that the witness should be instructed that isn’t an appropriate line of testimony.

The judge also called the jury back in, saying, “I don’t want them leaving here today with the last thing they heard being this witness’s understanding of Catholic teaching.” He told them to disregard the section of testimony.

Sullivan sent the jurors home and said that Heilbrun would get back on the stand Tuesday morning.

_____

©2026 MediaNews Group, Inc. Visit at bostonherald.com. Distributed by Tribune Content Agency, LLC.