Lindsay Clancy's defense attorney requested a mistrial Monday after the prosecution's psychologist testified that he asked the nurse if she knew suicide was a "mortal sin." The motion was denied by Judge William Sullivan, who instructed the jury to disregard the statement.

During the trial, Dr. Kirk Heilbrun, a psychologist who interviewed Clancy, stated that he noted she was Catholic and asked her, "isn't suicide a mortal sin?" Clancy's attorney, Kevin Reddington, objected and accused the prosecution of intentional misconduct.

Reddington argued this was the second time the state had raised the issue of religion and "mortal sin" during the proceedings, which he believes violates state law prohibiting the use of a witness's religious beliefs to attack credibility. Last week, the prosecution asked Sue Clancy, the mother of Clancy's husband, if she was Catholic and then if she knew murder was a mortal sin.

Judge Sullivan denied the mistrial motion but warned the state, telling them to "strongly" talk to the witness and emphasizing to the jury that religion "cannot be considered. It must be disregarded." Several jurors appeared surprised by the instruction.

Clancy, 36, is on trial for the murders of her three children: Cora, five, Dawson, three, and eight-month-old Callan, who died in their Duxbury, Massachusetts, home in 2023. She allegedly strangled them with exercise bands and then attempted suicide, an act that left her paralyzed. Clancy has admitted to killing her children but pleaded not guilty by reason of insanity, citing postpartum psychosis, and is seeking commitment to a mental health facility.

Dr. Heilbrun testified that he believed Clancy was not suffering from psychosis at the time of the killings but was severely suicidal. He described an "auditory command hallucination" Clancy experienced as "highly unusual." He also suggested that the phrase Clancy reportedly said to her children, "Go to God, baby," points to altruistic filicide—the killing of children out of love, driven by a disturbed belief that they would be better off dead.

This testimony followed that of defense witness Dr. Phillip Resnick, who stated that Clancy was "frankly psychotic" when she killed her children, driven by either "altruistic filicide" or "acutely psychotic filicide."

Closing statements are expected on Wednesday, following testimony from rebuttal witnesses and a hearing on the charges on Tuesday.