The 36-year-old former labor and delivery nurse faces three counts of first-degree murder in connection with the January 2023 deaths of her children: 5-year-old Cora, 3-year-old Dawson and 8-month-old Callan.
There is no dispute over who killed them.
The battle now unfolding in court centers on why it happened — and whether Clancy was legally responsible for her actions at the time.
Mother Describes Alarming Change
Musgrove’s testimony offered jurors an intimate account of what the family says was a dramatic deterioration in Clancy’s mental health during the months leading up to the tragedy.
According to the testimony, Clancy had revealed thoughts about hurting her children to both her mother and her then-husband, Patrick Clancy, by December 2022 — weeks before the killings.
The defense says those disclosures were part of a much broader pattern.
Family members have described Clancy as becoming increasingly anxious and fearful during the fall of 2022. She reportedly struggled with paranoia, suicidal thoughts and an intense fear of being left by herself.
Clancy repeatedly turned to mental health professionals for help.
Doctors prescribed a number of psychiatric medications while attempting to address her symptoms, and she also underwent a brief period of inpatient psychiatric treatment.
Her attorneys contend that the rapidly shifting treatment regimen unfolded while Clancy was suffering from a far more serious illness than her providers recognized.
The defense says she was experiencing postpartum psychosis and may also have suffered from previously undiagnosed bipolar disorder.
That argument will be central to whether Clancy spends the rest of her life behind bars.
Prosecutors Say Her Actions Show Planning
The prosecution has presented jurors with an entirely different interpretation of the evidence.
Rather than portraying Jan. 24, 2023, as an unpredictable psychiatric collapse, prosecutors have sought to establish that Clancy deliberately arranged circumstances that allowed her to be alone with the children.
Patrick Clancy testified that the day did not initially appear extraordinary.
But shortly after 5 p.m., Lindsay asked him to leave their Duxbury home to get medication and pick up dinner.
He was gone for less than an hour.
What he encountered upon returning would change the family forever.
Patrick noticed an unsettling silence inside the house before discovering his wife severely injured outside. She had apparently jumped from a second-story window in what authorities have described as a suicide attempt.
He then went into the basement.
There, he discovered the couple’s three children with exercise bands around their necks.
Cora and Dawson were pronounced dead that night.
Callan was transported to a hospital but died three days later.
Clancy survived her fall but sustained catastrophic spinal injuries. She is now paralyzed and uses a wheelchair.
Internet Searches Become Key Evidence
Prosecutors have also focused heavily on Clancy’s digital activity before the killings.
Jurors heard evidence concerning searches for subjects including hallucinations, psychosis, suicide methods and potential side effects of psychiatric drugs.
The state argues that Clancy’s online activity, combined with her decisions on the evening of the killings, supports its contention that she understood her conduct and intentionally created an opportunity to carry it out.
But the defense is turning that argument around.
Clancy’s attorneys maintain that researching hallucinations and psychosis could indicate that she realized her mental condition was deteriorating and was attempting to understand symptoms she could not control.
That competing interpretation illustrates the fundamental divide jurors must resolve.
Was the digital trail evidence of preparation?
Or was it evidence of a desperate woman searching for answers while descending into severe mental illness?
Doctors’ Testimony Complicates Defense Case
Clancy’s psychiatric care has consequently become one of the trial’s most heavily scrutinized issues.
Her defense has emphasized the number of medications she was prescribed, changes to those prescriptions and what attorneys describe as a poorly coordinated effort to address her worsening condition.
But medical professionals who encountered Clancy before the killings have provided testimony that could create problems for that argument.
Several providers testified that they did not observe indications that Clancy was psychotic or posed an immediate threat to her children when they treated her.
That gives prosecutors a powerful counterpoint to the defense’s claim that postpartum psychosis ultimately drove the killings.
The jury will have to weigh those professional assessments against testimony from relatives and others who say they witnessed a profound transformation in Clancy.
Nearly 70 Prosecution Witnesses Take Stand
The state rested its case Monday after presenting nearly 70 witnesses.
Those witnesses included Patrick Clancy, investigators, emergency personnel and medical professionals.
Now the defense has begun telling its side.
Clancy’s mother, sister and a former nursing colleague were among its first witnesses as attorneys attempt to establish that the woman who killed three children was suffering from such profound psychiatric illness that she cannot legally be held criminally responsible.
The consequences of that determination are enormous.
A first-degree murder conviction could result in life imprisonment without the possibility of parole.
A finding that Clancy lacked criminal responsibility because of mental illness could instead lead to her commitment to a psychiatric institution.
After years of investigations, medical examinations and legal maneuvering, the case has reached its defining question.
The jury isn’t being asked to decide whether Lindsay Clancy killed Cora, Dawson and Callan.
That fact is acknowledged.
They must decide whether the evidence proves a mother deliberately murdered her three children — or whether she was experiencing such a severe psychiatric breakdown that the law cannot hold her criminally responsible for the horrific acts committed inside the family’s Duxbury home.
