A Massachusetts judge rejected the defense's mistrial request in Lindsay Clancy's triple-murder trial after a prosecution expert referenced her Catholic upbringing, but not before rebuking the testimony as "absolutely inappropriate."

Judge William Sullivan ruled Monday afternoon in Plymouth, Massachusetts, that the trial would continue despite defense attorney Kevin Reddington's objection to testimony from forensic psychologist Dr. Kirk Heilbrun. Heilbrun, a Drexel University professor called by the prosecution, had begun telling jurors, "When I said suicide isn't a mortal sin," before Reddington cut him off with an objection. Sullivan sided with the defense on the substance, calling any reference to Clancy's religion out of bounds, but stopped short of declaring a mistrial. He instructed jurors to disregard the religion-related testimony entirely, WHDH reported.

The exchange was not the first time religion surfaced in the trial. Two days earlier, prosecutor Shanan Buckingham asked the victims' unnamed grandmother on the stand, "Are you an active member in the Catholic church?" When the grandmother answered yes, Buckingham pressed further: "So you're aware that murder is considered a mortal sin?" Sullivan intervened then, too, pulling Buckingham aside. Reddington called the pattern willful misconduct by the Commonwealth.

Heilbrun's testimony undercuts the insanity defense at its foundation

Monday's religion flare-up, though dramatic, was not the most consequential moment in the courtroom. Heilbrun's broader testimony posed a far more direct threat to Clancy's defense. He told jurors he concluded Clancy has bipolar disorder but is not psychotic, and that she did not suffer a psychotic break in January 2023, when prosecutors say she strangled her three children in their Duxbury, Massachusetts, home.

Clancy's defense rests almost entirely on a claim of postpartum psychosis. She has said she heard an external male voice commanding her to kill her children. Heilbrun dismantled that account point by point. He testified that the alleged hallucination lasted only the roughly 18 minutes it took to kill the children, and that Clancy reported never hearing the voice before or since.

Heilbrun did not hold back about how unusual that claim is:

"She heard a voice that she never heard before and she's never experienced it since, but she only experienced it for the 18 minutes or so that it took to kill the children. To put it mildly, that would be a very, very unusual pattern or manifestation of how this kind of thing comes about."

A hallucination that appears once, lasts exactly as long as the killings, and never returns is not how command hallucinations typically present, Heilbrun told the jury. Fox News reported that Heilbrun identified three specific points where Clancy's hallucination account more closely resembled exaggerated or fabricated symptoms. Only one point appeared genuine, and one was what he described as "kind of mixed."

He also challenged what Clancy said after the killings. When her then-husband Patrick found her injured on the ground in their backyard, she had jumped from a second-floor window, he asked, "What did you do?" Lindsay answered, "I tried to kill myself." She did not mention the voice. Heilbrun told jurors that if she had truly experienced a command hallucination, she might have said something like, "I did what I had to do. I did what the voice said."

The case has drawn intense public attention and sharp debate over the double standard applied to defendants who attract online sympathy. Clancy's supporters have rallied around the postpartum psychosis narrative. Heilbrun's testimony put that narrative under direct, clinical scrutiny, and found it wanting.

Prosecution built a premeditation case brick by brick

AP News reported that Heilbrun concluded Clancy killed her three children because she planned to kill herself and did not want to leave them behind. He testified that she told each child "Go to God, baby" while strangling them, a detail that cuts against the idea of a woman overtaken by psychosis and toward one acting with grim, deliberate purpose.

A second prosecution expert, Dr. Avram Mack, also testified that Clancy showed no evidence of psychosis and could distinguish right from wrong during the killings, according to AP News.

The prosecution has also pointed to evidence of planning. The Washington Examiner reported that prosecutors allege Clancy searched a restaurant on Apple Maps just before sending Patrick away from the house, a detail that suggests she engineered time alone with the children. That kind of calculated preparation is difficult to square with an insanity defense built on sudden, involuntary psychosis.

Earlier in the trial, evidence showed Clancy had texted her husband about takeout roughly an hour before the killings, another detail prosecutors have used to argue she was functioning normally, not in the grip of a psychotic episode.

Clancy herself conceded the physical facts of the case weeks ago. The New York Post reported that she spoke in court for the first time on August 4 to stipulate to DNA evidence, blood evidence, the exercise bands used in the killings, and chain of custody. Judge Sullivan confirmed she understood what she was doing: "You are basically relieving the Commonwealth of its burden to prove certain facts. Is that what you want to do?" Clancy answered, "Yes, your honor."

Her attorney Reddington acknowledged the concession plainly: "We have not contested the government's case." The defense's entire strategy hinges on convincing jurors that Clancy was legally insane, that she could not appreciate the wrongfulness of her actions because postpartum psychosis had overtaken her mind.

Clancy was on six psychiatric medications at the time of the killings

The New York Post also reported that Clancy was taking six psychiatric medications when she killed her children on January 24, 2023, and had been prescribed 15 different drugs in the four months before the murders. After strangling all three children, she attempted suicide by slitting her wrists and jumping from a second-story window, leaving her partially paralyzed.

The medication history adds a layer of complexity. It confirms Clancy was under psychiatric care and struggling. But it also raises a question the prosecution has pressed: if she was lucid enough to plan the logistics of getting Patrick out of the house, search for a restaurant on her phone, and carry out the killings over 18 minutes, was she truly unable to tell right from wrong?

High-profile murder trials often turn on a single piece of testimony or a courtroom moment that shifts the jury's perception. Judicial conduct has come under scrutiny in other recent cases as well, though in the Clancy trial, Sullivan has moved to keep the proceedings on track despite the prosecution's missteps on religion.

Cross-examination and closing arguments loom this week

Reddington is expected to cross-examine Heilbrun on Tuesday, which the court described as the expected last day of testimony. Closing arguments could come as soon as Wednesday. The defense will need to blunt Heilbrun's clinical conclusions and reframe the 18-minute hallucination claim as plausible, a tall order after the prosecution's expert called it "very, very unusual" twice in the same sentence.

Sullivan's decision to deny the mistrial keeps the case moving toward a verdict. He found the religion-related testimony objectionable enough to instruct jurors to disregard it, but not prejudicial enough to scrap weeks of trial proceedings. Whether that instruction sticks in jurors' minds, or whether the reference to mortal sin lingers, is something neither side can control.

The facts the prosecution has assembled tell a story of planning, execution, and aftermath that fits premeditated murder more comfortably than sudden psychosis. Disturbing evidence has defined other recent high-profile trials, but few cases have forced a jury to weigh a defendant's mental state against this volume of contradictory detail.

Three children are dead. The woman who killed them does not dispute that she did it. The only question left is whether a jury believes a voice no one else heard, that appeared from nowhere and vanished just as fast, absolves her of responsibility. The evidence says otherwise.