Stabbed five times, Claudio Cara lay dying on the kitchen floor of his Oshawa home. The final thrust of the knife — one Cara preferred for slicing Italian sweets — was likely the fatal one. The blade protruded from the 56-year-old’s chest, the handle missing.

The business of estimating exact time of death is inaccurate. But in this case, the precise answer as to when Cara’s heart last beat lay within him — in data captured by a pacemaker.

The data showed Cara’s heart stopped beating on Feb. 15, 2012, at 10:35 a.m., and would prove crucial in a circumstantial case in which Durham regional police were convinced Cara’s son Frank — who lived with his father — was good for the murder.

Yet, for months, the results of a pacemaker analysis ordered by police was not a factor in the investigation.

During that time, police would track Frank’s car, intercept his calls, pore over text messages and ask his sister to wear a wire and confront him. Frank maintained his innocence and co-operated with investigators.

Ultimately, police charged Frank with second-degree murder.

By the time Frank’s lawyers came across the pacemaker data in a pile of disclosed documents and had an expert analyze it, Frank, who had no criminal record, had been in jail for 10 months, having been denied bail.

The upshot: Frank was not home when his father’s heart beat its last.

Frank, who had four witnesses, including his sister, confirm he was visiting his ill grandmother for several hours the morning his father died, was granted bail the day after his lawyers showed police and the Crown the results of their analysis. Months later, the Crown told court that medical evidence regarding time of death had surfaced and there was no longer a reasonable chance of a conviction. At the request of the Crown, the charge against Frank Cara was withdrawn in December 2013.

Allegations contained in a recently filed statement of claim — in which Frank Cara is seeking $5 million in damages from Durham police for wrongful arrest and detention, investigative “tunnel vision” and negligence — shed light on a case that would disintegrate due to a telltale heart device.

The Star found a handful of cases worldwide where pacemaker data proved pivotal in a murder case. In one Australian case, pacemaker time data worked the other way, helping convict a man in the 2000 slaying of a 72-year-old.

The Cara case may be one of the first times such data proved critical in supporting an alibi.

At best, police may have missed or misinterpreted the pacemaker evidence. At worst, according to allegations made in the statement of claim, detectives chose to ignore and bury it, smearing Frank Cara’s reputation, and destroying his career and relationships in the process.

The suit names as defendants the Durham police detectives Tom Dingwall, Mark Sheridan and Paul Sartain, Chief Paul Martin and the Durham police service. The allegations have not been proved and police have yet to file a statement of defence.

Because the case is now before the courts, a Durham police spokesperson said the service would not be speaking about the case. “We must respect the current legal process underway,” said Dave Selby.

The Star, through Selby, offered the named officers an opportunity to address the allegations. None took up that offer, which is also not unusual in a lawsuit.

What follows is based on interviews with Frank Cara (who has hired Toronto lawyers Brian Gover and Fredrick Schumann to handle the civil suit), Cara’s relatives, his criminal lawyer Bernie O’Brien, allegations contained in the statement of claim, and court transcripts.

The pacemaker

Pacemakers detect changes in the heartbeat and deliver electrical impulses to regulate the pulse. They have an internal clock and memory that records events, not unlike an aircraft’s black box.

Claudio Cara, a lifelong GM worker, had one implanted in 2005 for a condition that led to early retirement in 2007.

Pacemakers — Model #5386 from St. Jude Medical Inc., in Claudio’s case — are designed to prevent slow heart rhythms. Once implanted, the devices, about the diameter of a Canadian two-dollar coin, monitor the regular beat and deliver when necessary just enough of a shock to trigger the heart to beat.

Before being implanted, the device is hooked to a “programmer,” essentially an oversized laptop computer. This includes embedding heart pacing instructions, date and time, and can include information about the patient and the clinic that installed the device.

Once implanted under the skin, any setting can be altered by an external wand that communicates with the device by radio signals.

Some models, such as Claudio’s, have an “auto-capture” feature that allows the pacemaker to record when an electrical impulse delivered to the heart results in an effective heart contraction — or does not.

When the heart no longer gets oxygen, no amount of shocking can cause it to beat again. The device records when this happens.

Iqwal Mangat, a cardiologist at St. Michael’s Hospital who specializes in cardiac electrophysiology, is familiar with the model Claudio used.

In the event of a stabbing that leads to oxygen being cut off from the heart, the heart loses its “ability to contract,” says Mangat. “Then no amount of electrical activity is going to cause the heart to contract.” The device records a “loss of capture” event.

On Feb. 15, 2012, the device in Claudio’s chest registered two such events. According to his son’s statement of claim, an analysis of the data showed they occurred a minute apart, at 10:35 and 10:36 a.m.

In other words, that was when Claudio Cara died.

The murder

Frank Cara rose early and left the house to visit his maternal grandmother. He was nowhere near his home at 10:30 a.m.

Frank, then 28, and his father had been living together since the elder Caras had separated in 2005. Frank’s older sister moved out on her own. Frank, who was a drywall apprentice, told the Star he loved his father.

Frank arrived at his grandparents’ home around 9:15 a.m. He called his father’s cellular and home phones to let him know he was staying for lunch. There was no answer. Frank, according to the statement of claim, returned home just after noon to find the door ajar and his father on the kitchen floor. There was blood, and a piece of steel sticking out of his chest.

Frank told the Star he recognized the knife as one from the kitchen, which his father liked to use at Christmas to cut torrone, a traditional Italian yule log made of nougat. The handle was gone.

Frank pounded on the door of a neighbour’s house, and they dialed 911. It was 12:10 p.m.

Tunnel vision?

When police should have been focusing on time of death, they instead were sizing up Frank as a suspect and spent months building a circumstantial case, he alleges in his lawsuit.

Frank co-operated with every request from police but one, that he take a polygraph test. He considered the tests unreliable.

Durham police “took Frank’s refusal as further evidence of his guilt,” his suit alleges.

He did supply DNA, fingerprints, access to his vehicle and clothes, and he was quick to respond to police questions.

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According to allegations in the statement of claim, police, however, waited days to ask for Frank’s clothing, which by then had been washed. They spent six days searching the house, but obtained another warrant three months later to look again, after “numerous” people had been in and out. They waited eight months to ask for blood for a DNA analysis.

“Within a day of the homicide, Frank Cara was almost accused of being the perpetrator, long before any sensible investigation had been undertaken,” Bernie O’Brien, one of Frank’s criminal lawyers, told the Star. “On the flimsiest of evidence, they came to him and suggested that he had been complicit.”

Frank alleges in the statement of claim that police asked him repeatedly about the location of the knife handle.

They also employed wiretaps, vehicle tracking, and other intrusive techniques in trying to make their case. Digging through text messages and through interviews, police looked into Frank’s cocaine use and drug payments (in the $40 to $80 range) that didn’t appear to be in serious arrears.

The suit alleges Officer Dingwall told Frank’s family and friends that Frank “was a drug addict, as well as a liar and a murderer.” Officer Sartain, the suit alleges, told Frank’s girlfriend, Jennifer Tureski, that Frank shouldn’t be around her children and that if he did not move out, “police would call the Children’s Aid Society and report her.”

While the investigation drove a wedge between Frank and some family members, Tureski and an aunt — Maria Ziccarelli, Claudio’s sister — and her husband stood by him from the beginning.

Ironically, investigators early on confronted Frank with the fact that his father had a pacemaker and they could retrieve “a lot of information” from it.

“Go ahead and do that,” Frank recalled telling them.

Police, according to the statement of claim, received an analysis of the pacemaker data from St. Jude Medical in July 2012.

Police appealed publicly for information in fall 2012, holding a press conference with Frank’s sister. On Nov. 6, officers, without a warrant, charged Frank with second-degree murder.

Frank was denied bail and landed at the “superjail” in Lindsay. During his 10 months there, Frank told the Star he had to learn the rules, including to turn a blind eye whenever prison justice resulted in a beating.

“You could hear the thuds and the screams.”

‘Buried’ data

While preparing for a preliminary hearing, Frank’s defence lawyers discovered the pacemaker analysis amid 10,000 to 15,000 pages of disclosure.

“It was just buried in sort of the subfile that was deemed to be marginally relevant,” O’Brien said in an interview. “That was obviously an oversight on someone’s part at the Durham police service.”

O’Brien believes police and the Crown were under the impression nothing useful would come of the pacemaker analysis, and the results were not closely read, but filed away.

O’Brien and co-counsel Tom Balka, however, did read them closely.

In August 2013, the defence presented its own analysis to the Crown and Frank was granted bail and placed under house arrest while police and the Crown looked into the data.

In November, St. Jude Medical confirmed the results.

On Dec. 23, as southern Ontario endured the beginning of a blackout brought on by an ice-storm, the power was on at an Oshawa courthouse.

A Crown attorney told the court that based on medical evidence, there was no longer a reasonable prospect of conviction. He asked that the murder charge against Frank be withdrawn.

It was. Frank walked out of court that day no longer accused of killing his father. There was no apology for the time he had spent in jail and under house arrest.

Who killed Claudio?

Claudio Cara is buried at Resurrection Cemetery in Whitby. Feb. 15 marks the three-year anniversary of his death. His son has no indication police have any strong leads or suspicions.

The Durham police website lists the slaying as an unsolved homicide. A posting dated June 12, 2014, says a “project team” is investigating and asks anyone with information to contact the homicide unit or CrimeStoppers.

“I lived there, I found him,” Frank told the Star. “So there’s already a cloud over top of that at the beginning, and it’s understandable.”

But, he said, police should not “form an opinion or a judgment until you have everything on the table . . . My life is ruined.”

He suspects prospective employers Google his name and stories of his arrest are a click away.

Frank refused to speculate about who killed his father. But he wants answers.

“I owe it to my father … to get our name back to where it once was.”

Correction – February 24, 2015: This article was edited from a previous version that contained a direct quote from Frank Cara’s statement of claim alleging police chose to “ignore and bury” the data. In fact, it was not a direct quote, but, according to his lawyers, a reasonable paraphrase of allegations made in the document. As well, Cara is suing the Durham Regional Police Services alleging that the arrest was wrongful in that it stemmed from a flawed investigation.