The final actions of Lindsay Clancy, before the tragic deaths of her three children, were seemingly documented by devices within her home.
This Massachusetts mother stands accused of strangling her children—Cora, five, Dawson, three, and eight-month-old Callan—in the basement of their Duxbury residence in January 2023.
While Clancy does not contest the fact that she killed her children, she has entered a plea of not guilty. She argues she was not in control of her actions due to postpartum psychosis, exacerbated by a potent mix of prescribed medications.
During the 14th day of her trial on Monday, prosecutors unveiled data from Clancy’s Apple Watch and iPhone. These devices tracked her heart rate, phone usage, and movements around the house, which abruptly stopped recording at 5:38 PM.
This crucial evidence was brought forth by Ian Whiffin, a digital forensics expert from Cellebrite, who conducted a comprehensive data analysis from Clancy’s iPhone 13 for the prosecution’s case.
Her watch logged a final heart-rate measurement of 57 beats per minute at precisely 5.23.52pm. Whiffin did not provide a medical explanation for the reading or determine why the device stopped collecting data.
Ten minutes later, her iPhone detected movement up one flight of stairs, followed by a second flight approximately five minutes afterward.
During that window, Patrick Clancy called his wife’s phone before a 14-second return call was placed from the locked iPhone.
‘After 5.38, it’s pretty much blackout,’ defense attorney Kevin Reddington said as he challenged how much the digital evidence could establish. Whiffin agreed that the health data could not show what Clancy, or anyone carrying the devices, was doing after that point.
On Monday, prosecutors revealed how Clancy’s Apple Watch and iPhone created a minute-by-minute digital record of her movements. Above shows times the device recorded her walkng up flights of stairs
Lindsay Clancy is accused of strangling Cora, five, Dawson, three, and eight-month-old Callan in the basement of their Duxbury home in January 2023. Here she is with her now ex-husband and three children
An exact minute-by-minute time for the strangulation of the children has not been definitely established by a single timestamp.
However, trial evidence and phone records show the killings occurred in a narrow window roughly between 5.34pm and 6.09pm while her husband was out of the house.
Whiffin, who works for digital intelligence company Cellebrite, told the court that he had extracted and analyzed more than 1,000 phones since 2013 and had testified approximately 28 times in courts around the world.
Apple Health combines information recorded by an iPhone with data collected by connected devices, including an Apple Watch.
The application can store heart rate, steps, distance traveled and flights climbed, creating a detailed record of a user’s physical activity.
Whiffin said the heart-rate data came directly from a device paired with Clancy’s phone and named ‘Lindsay’s Apple Watch.’
Sensors on the back of the watch periodically measured her pulse and transferred the readings to her iPhone through Bluetooth.
Clancy’s heart rate ranged from approximately 50 to 122 beats per minute throughout January 24, averaging in the high 80s or low 90s.
Her watch logged a final heart-rate measurement of 57 beats per minute at precisely 5.23.52pm, but Whiffin did not offer a medical explanation for the reading or say why the device stopped collecting data
Cora, five, Dawson, three, and eight-month-old Callan were strangled at the family home in January 2023
What I saw in the Lindsay Clancy trial brought the courtroom to tears
I’m Rachel Sharp, US Crime Desk Editor, and I have been in court covering every day of the Lindsay Clancy trial.
The trial, as many of you will know, is streamed live for the world to see. But not everything is shown to the public; some things are simply too distressing – and these moments have had Lindsay, her parents, the jurors, and members of the media in tears.
I have shared my experiences in our new podcast series, which you can listen to for free by clicking here
The final measurement was recorded at 5.23.52pm, when her pulse was 57 beats per minute.
There were no further heart-rate readings after that point. Whiffin said the watch could have stopped recording because it had been removed, turned off or run out of battery.
The stair activity was recorded by Clancy’s iPhone rather than her Apple Watch.
Both devices contained sensors capable of detecting steps and changes in elevation, Whiffin explained.
A flight of stairs is logged when a device detects movement alongside an increase in elevation of approximately 10 feet.
Clancy’s phone recorded one flight completed at approximately 5.33pm and another at around 5.38pm.
The data grouped those movements into a single five-minute event, but Whiffin said that did not mean the user had spent five continuous minutes climbing stairs.
Instead, the phone detected one completed flight and then registered another approximately five minutes later.
At 5.33pm, Patrick placed a call to Clancy’s phone.
The call log listed the conversation as lasting zero seconds, but Whiffin testified that the record indicated it was answered.
Approximately one minute later, Clancy’s phone placed an outgoing call to Patrick that lasted 14 seconds.
Whiffin also recovered internet searches made in the weeks before the children’s deaths, including ‘how quickly does Wellbutrin work,’ ‘ketamine for suicidal ideation,’ ‘symptoms of postpartum psychosis’ and ‘psychosis symptoms’
Crime scene photos show the inside of the basement where the children were found strangled
Her iPhone had last been unlocked at 5.13pm and was locked again approximately two minutes later.
Whiffin explained that an iPhone user can return a missed call through a lock-screen notification without entering a passcode or unlocking the device.
By 5.33.34pm, the phone had already recognized that it was approximately 10 feet higher than during its previous measurement, meaning the first flight of stairs had been completed. The second flight was detected at approximately 5.38pm.
Patrick called again at 6.09pm, but that call went unanswered.
Prosecutors used the combined Apple Health, phone and device-usage records to reconstruct Clancy’s apparent movements and activity that evening.
However, defense attorney Reddington challenged how much the digital evidence could establish, emphasizing that it tracked the devices, not necessarily the person carrying them.
Although Clancy does not deny killing her children, she has pleaded not guilty, claiming she is not criminally responsible because she was suffering from postpartum psychosis after being prescribed a powerful cocktail of drugs
He asked whether the phone and watch could have been put down or stopped recording while someone continued moving around the house.
Whiffin agreed. ‘You just don’t know, right?’ Reddington asked. ‘Yes,’ Whiffin replied.
The defense also questioned the accuracy and reliability of Apple Health data, noting that Whiffin had conducted tests in which some measurements were ‘off a little bit.’
Whiffin explained that both an iPhone and Apple Watch can record the same movement, sometimes creating duplicate entries with slightly different timestamps.
He said he removed overlapping records from his analysis so that a single climb detected by both devices would not be counted twice.
Whiffin acknowledged that a phone could mistakenly record a flight of stairs if someone was traveling in a vehicle up a hill while the device simultaneously detected movement resembling steps. He described those errors as rare.
The phone data also recorded Clancy’s activity shortly before the final heart-rate measurement.
At 4.13pm, Apple Maps was used to plot a route from the family home to a restaurant called 3V.
One hour later, Clancy’s phone was unlocked, and Safari was used to search for Pedia-Lax liquid stool softener.
The messaging application was then opened, and a text was sent to Patrick reading: ‘PDLX liquid stool softener.’
The phone was locked at approximately 5.15pm and was not unlocked again, although the later call to Patrick was placed through the lock screen.
Whiffin also recovered internet searches made in the weeks before the children’s deaths, including ‘how quickly does Wellbutrin work,’ ‘ketamine for suicidal ideation,’ ‘symptoms of postpartum psychosis’ and ‘psychosis symptoms.’
The digital evidence provides a detailed but incomplete record of Clancy’s activity that evening.
Her watch captured one final heart-rate reading before falling silent, while her phone continued documenting movement for another 15 minutes.
After 5.38pm, the devices left investigators with a blank space and no record of what happened next.
