data, analysed by Cellebrite digital-forensics expert Ian Whiffin, does not show traditional security-camera video of the basement or the killings themselves. Instead it comes from the sensors in the phone and watch that detect steps and changes in elevation. A “flight climbed” is logged when movement coincides with an approximate 10-foot rise. The phone recorded the climbs at approximately 5:33pm and 5:38pm; the watch had already stopped collecting heart-rate data.
Prosecutors have used the timeline to support their theory that Clancy remained mobile and purposeful while her husband Patrick was out of the house collecting takeaway and medicine – a trip she had initiated. Patrick’s movements that evening have been independently verified by surveillance video from a CVS pharmacy and a restaurant, placing him away from the home during the critical window.
The digital evidence has been described in court coverage as a potential turning point because it undercuts online speculation and certain defence suggestions that Clancy was already incapacitated or that someone else was involved. The phone continued to register stair climbs after Patrick had left, consistent with the prosecution narrative that she took the children to the basement, carried out the acts, returned upstairs, locked the bedroom door, crushed and ingested pills, cut herself, and jumped.
Whiffin told the court the stair activity was recorded by the iPhone rather than the watch. Both devices contain sensors capable of detecting elevation changes, but the phone alone logged the later movements. He emphasised that the five-minute grouping of the two climbs did not necessarily mean continuous climbing; it reflected the way the system aggregates data.
The same extraction showed the phone’s last unlock at 5:13pm, used to search for a stool softener and send a message to Patrick. After that the device was locked and not unlocked again, although a brief call was later made. The heart-rate reading of 57 bpm at 5:23pm has drawn particular attention; Whiffin offered no medical interpretation of the figure or explanation for why data collection then ceased on the watch.
Separate testimony has established that Clancy, a labour-and-delivery nurse, was in the habit of checking home security cameras on her phone while working night shifts – behaviour a former colleague described as the actions of an anxious, attentive mother rather than a warning sign. No public evidence has emerged of actual security-camera footage capturing the events inside the house on the night itself. The “devices inside her home” referenced in reporting are the phone and watch that travelled with her.
The trial, now in its later stages in Plymouth Superior Court, has already featured graphic crime-scene photographs, the harrowing 911 call made by Patrick Clancy, and extensive testimony about Clancy’s mental-health history, medication regimen, and internet searches in the weeks and months before the deaths. Searches on devices linked to the household included terms related to psychosis, hallucinations, bipolar disorder, and, on one computer, a page about suicide methods months earlier. Defence lawyers have repeatedly stressed that shared devices make it impossible to prove who performed every search.
Patrick Clancy has testified about returning home to find the house unnaturally quiet, discovering blood in the locked master bedroom, finding his wife on the frozen ground outside, and then locating the children in the basement with exercise bands around their necks. He removed the bands and attempted CPR while on the phone with emergency services. The 911 recording, played for the jury but restricted from public dissemination, captures his screams and the moment he told the dispatcher “she killed the kids.”
Prosecutors have argued the killings were meticulous: the children were taken to the basement one by one or in groups, strangled with separate bands, and left there while Clancy went upstairs to attempt suicide. The defence maintains she was in the grip of a severe mental illness that robbed her of the capacity to appreciate the wrongfulness of her actions or to conform her conduct to the law under Massachusetts standards for lack of criminal responsibility.
The digital movement data has become a focal point because it offers an objective chronological spine for the critical half-hour. It places Clancy’s phone moving through the house after Patrick had left and while he was still documented at the pharmacy and restaurant. Combined with the heart-rate log and the final device interactions, it has been presented as evidence that she was physically active and in control of her phone during the period the children died.
Jurors have also been shown crime-scene video of the master bedroom, blood evidence inside and outside the house, and earlier family footage from a museum visit two weeks before the tragedy in which Clancy appears engaged with the children. A rare jury view of the former family home allowed them to walk the layout, including the basement and the height of the window from which she fell.
Clancy herself has not testified. She has been present in court, often emotional during testimony about the children. Her parents and other relatives have attended. Patrick Clancy, who has since remarried, has described the night as the moment his life was destroyed.
Legal observers note that the sensor data does not capture the acts in the basement themselves and cannot speak directly to Clancy’s mental state. What it does provide is a sequence of physical movements and device interactions that the prosecution says is inconsistent with a total loss of control and consistent with purposeful conduct. The defence is expected to argue that any movements occurred while she was already in a dissociated or psychotic state, and that the data proves nothing about her capacity for criminal responsibility.
As the trial nears its end, with closing arguments anticipated imminently, the digital reconstruction of Clancy’s last steps through the house has become one of the most closely examined pieces of evidence. It is not grainy security-camera footage of a figure moving through rooms. It is the cold numerical record of a heart rate, locked and unlocked screens, and stairs climbed – a silent, precise ledger of the minutes that changed everything.
Whether that ledger ultimately helps the jury decide that Lindsay Clancy knew what she was doing, or that she was too ill to know, will be determined in the coming days. For now, the data from the devices she carried has given the court its clearest picture yet of how the final hour unfolded inside the quiet suburban home on Summer Street.
The three children – Cora, Dawson and Callan – remain at the centre of a case that has gripped the nation, forcing uncomfortable questions about postpartum mental health, medication, and the limits of the criminal-responsibility defence. The digital trail has sharpened those questions rather than resolved them. It has simply made the timeline harder to ignore.