A United States judge, William Sullivan, has declared a mistrial in the high-profile murder trial of Lindsay Clancy, an American woman accused of killing her three children, after the jury reached a ᴅᴇᴀᴅlock.

Judge Sullivan announced the decision on Friday, September 4, 2026, at the Plymouth County Superior Court in Mᴀssachusetts, but temporarily froze the ruling to allow the defence team time to file an appeal with a higher court.

The 12-member jury panel reported that it was split 11-1, with the majority favouring a verdict of not guilty by reason of insanity. Under US law, a murder conviction requires a unanimous decision from all 12 jurors.

Clancy, 36, does not deny strangling her three children, Cora, 5, Dawson, 3, and Callan, 8 months, at their family home in Duxbury, Mᴀssachusetts, in January 2023.

However, her defence team maintains that she suffered from postpartum psychosis, a severe mental health condition that made her criminally non-culpable.

Defence attorney Kevin Reddington argued that Clancy was responding to auditory hallucinations commanding her to commit the acts, adding that she had repeatedly sought medical help prior to the incidents.

Following the killings, Clancy attempted suicide by jumping from a second-story window, which left her paralyzed from the waist down.

Conversely, state prosecutors argued that the defendant meticulously planned the killings and was aware of her actions.

Following the mistrial declaration, prosecutors will decide whether to retry the case before a new jury.