Psychologist Details Lindsay Clancy’s First Words After Children’s Deaths as Defense Later Moves for Mistrial

A forensic psychologist took the stand in Lindsay Clancy’s murder trial Monday, offering jurors his assessment of her mental state and describing what he believes may have motivated the deaths of her three children.

Dr. Kirk Heilbrun, a rebuttal witness for the prosecution, testified Aug. 24 that he evaluated Clancy over three days in April 2026. He said he diagnosed her with Bipolar II disorder but found no evidence that she was experiencing an acute psychotic episode.

 

Clancy, 36, is charged in the January 2023 deaths of her children, 5-year-old Cora, 3-year-old Dawson and 8-month-old Callan. Prosecutors allege that she strangled the children with exercise bands at the family’s Duxbury, Massachusetts, home.

Clancy has not disputed that she killed her children. Her defense, however, has pleaded not guilty by reason of lack of criminal responsibility and argued that she was suffering from postpartum psychosis and had been overmedicated.

Heilbrun told jurors that Clancy had experienced depressive episodes but had not suffered manic episodes associated with Bipolar I disorder. He acknowledged that reaching her diagnosis was complicated, while noting that she appeared to respond positively to medications used to treat the condition.

The psychologist also discussed what he described as Clancy’s intrusive thoughts. Among the thoughts she reported were beliefs that her brain was damaged, that she needed to die and that she needed to harm her children.

Heilbrun said he ultimately considered two possible explanations for why Clancy committed acts that he described as dramatically inconsistent with her personality.

One possibility, he testified, was that Clancy believed killing her children would spare them from suffering after her death and allow them to remain together in heaven.

The other possibility was acute psychosis — a theory Heilbrun said he ultimately rejected.

He pointed to one of Clancy’s earliest statements after the killings as part of his reasoning.

When Patrick Clancy returned home and discovered his children and his injured wife, he asked Lindsay what had happened. According to Heilbrun, her response was simply, “I tried to kill myself.”

 

Heilbrun said that answer did not fit what he would typically expect from someone acting under the influence of hallucinations or an acute psychotic episode. In such a circumstance, he suggested, a person might instead attribute their actions to a perceived command or voice.

Clancy has previously said that she heard a male voice during the roughly 18-minute period in which the children were killed.

According to Heilbrun’s testimony, she reported that the voice told her: “This is your last chance. You have to kill the kids so you can kill yourself.”

The psychologist questioned the timing and nature of that reported voice, saying it appeared unusual that Clancy described hearing it only during the killings. He also noted that Clancy had provided inconsistent descriptions of what the voice supposedly told her to do.

Heilbrun additionally described what he called “altruistic filicide,” explaining that Clancy may have believed her children would suffer without her and that killing them would allow them to be “together in heaven.”

He testified that Clancy said words to her children as they died, including, “Go to God, baby. Go to God.”

The testimony later took an unexpected turn when Heilbrun referred to Clancy’s Catholic faith during another answer.

Clancy’s attorney, Kevin Reddington, immediately objected and requested a mistrial. He argued that references to Clancy’s religion had repeatedly surfaced during testimony even though he believed her faith was irrelevant to determining her criminal responsibility.

Prosecutors disputed that they had intentionally introduced the issue.

Judge William Sullivan rejected the defense request for a mistrial but ordered the matter addressed and instructed jurors that the reference to religion was not something they should consider.

“The religion that the defendant was raised with is absolutely an inappropriate area of testimony,” Sullivan told the jury. “It is to be stricken. It is not to be considered.”

The judge emphasized that jurors were not to use the religious reference in evaluating the case.

The jury was subsequently dismissed for the day. Heilbrun is expected to return to the witness stand Tuesday to complete his testimony.

The prosecution is expected to call one additional rebuttal witness before both sides deliver their closing arguments.

The trial centers on the question of Clancy’s mental state at the time of the killings. Prosecutors have argued that she was depressed but understood what she was doing, while the defense maintains that postpartum psychosis and medication-related problems left her unable to appreciate the wrongfulness of her actions.

After weeks of testimony, the jury will ultimately have to determine whether Clancy is legally responsible for the deaths of her three children.