Plymouth (United States) (AFP) - A judge declared a mistrial on Friday after a jury was unable to reach a unanimous verdict in the high-profile case of an American woman who killed her three young children.

Lindsay Clancy, 36, acknowledged strangling Cora, five, Dawson, three, and Callan, eight months, but claimed she was suffering from postpartum psychosis, excusing her from criminal responsibility.

After seven days of deliberations the 12-member Massachusetts jury was unable to reach a unified decision, as required in criminal proceedings in the United States.

Eleven jurors were in favor of finding the 36-year-old Clancy not guilty by reason of insanity, but they were opposed by a single holdout.

“At this point, I’m going to declare that the jury is deadlocked, and I’m going to declare a mistrial,” Judge William Sullivan said.

Prosecutors must decide now whether to try the case again with a new jury.

“I’ll be making that decision shortly,” Tim Cruz, the Plymouth County district attorney, told reporters.

Clancy will remain incarcerated pending a possible new trial.

Clancy’s televised five-week trial, which featured more than 80 witnesses and days of distressing testimony, has sparked debate in the United States over maternal mental health and drew a reaction on Friday from President Donald Trump.

“It’s a horrible tragedy,” Trump told reporters at the White House. “I assume there’s going to be another trial.”

Clancy pleaded not guilty by reason of insanity, saying she heard a voice ordering her to kill her children.

Her lawyers said this was caused by postpartum psychosis, a condition that medical experts say affects about one to two women in every 1,000 births.

Prosecutors rejected that argument, saying Clancy had carefully planned the murders of her children and was able to understand the consequences of her actions.

Psychiatrists and people close to Clancy, as well as her estranged husband, were among the witnesses who testified about her fragile mental health.

- ‘Lousy medical care’ -

Dozens of women dressed in pink showed up at the court in Plymouth to extend their support for Clancy – and to make a statement about women’s health more generally.

During closing arguments, Kevin Reddington, Clancy’s lawyer, said she had made numerous pleas for help before the killings but had received “lousy medical care” from the doctors she consulted.

After the murders at the family home in Duxbury, Massachusetts, in January 2023, Clancy jumped from a second-story window in an apparent suicide attempt that left her paralyzed from the waist down and confined to a wheelchair.

The former nurse faced life in prison without the possibility of parole if found guilty of first-degree murder.

Jurors were also given the option of finding Clancy guilty of second-degree murder, manslaughter, or not guilty by lack of criminal responsibility – a verdict that would see her confined to a psychiatric facility.

The trial has revived memories of a similar case that also captivated the country 25 years ago, that of Andrea Yates, a Texas mother who drowned her five children in 2001.

Yates was initially convicted and sentenced to life in prison, but she was found not guilty by reason of insanity at a 2006 retrial and committed to a psychiatric hospital.