Religion became a flashpoint Monday in the trial of Lindsay Clancy, a Massachusetts mother charged with murdering her three children — Cora, 5, Dawson, 3, and Callan, 8 months — in Duxbury, Mass., in January 2023. For the second time, a reference to "mortal sin" prompted Judge William Sullivan to strike testimony and instruct jurors to disregard it. Clancy, 36, raised Catholic, pleaded not guilty by reason of postpartum psychosis. Her lawyer, Kevin Reddington, argues she acted under auditory hallucinations; prosecutors claim she planned the killings and used exercise bands to strangle the children.

Prosecution psychologist Kirk Heilbrun testified Clancy said "Go to God" during the strangulations and asked if suicide is a mortal sin. Reddington objected and moved for a mistrial, which Sullivan denied but warned religion is "absolutely an inappropriate area of testimony." Last week, prosecutor Shanan Buckingham asked Clancy's former mother-in-law, Susan Clancy, if murder is a mortal sin, drawing a similar rebuke. Loyola Law professor Laurie Levenson called the prosecution's approach "very dangerous."

Earlier, defense cross-examination of forensic psychiatrist Dr. Avram Mack ended abruptly when Reddington closed his binder, saying, "I don't care." Rebuttals continue Tuesday; closing arguments may follow Wednesday in Plymouth, Mass.