The sign at the Calgary Courts Centre in Calgary is shown on Friday, Jan. 5, 2018. THE CANADIAN PRESS/Bill Graveland

CALGARY - Jurors in the trial for a couple charged in their 14-month-old son's death heard starkly differing accounts Tuesday of why he died.

Jennifer and Jeromie Clark of Calgary have pleaded not guilty to criminal negligence causing death and failure to provide the necessaries of life for their son John.

"This is not a whodunnit. There's no mystery of what happened to John," prosecutor Shane Parker said in his closing arguments.

The Crown presented evidence from an array of medical professionals that suggested John could not fight off a staph infection because he was malnourished, and that he was close to death by the time his parents took him to hospital.

But defence lawyers argued that while John was sick, he was not malnourished or suffering an infection. They said his death was the fault of doctors who treated him.

Emergency and intensive care doctors testified that when the boy arrived in hospital, his heart rate and temperature were abnormally low, he was covered in a rash and some of his toes were blackened. They said that suggested he was in the final stages of septic shock.

"The hospital did not break John. John was essentially dead on arrival," Parker said.

The Crown presented evidence that the Clarks searched online for natural cures for gangrene and poor circulation in the weeks leading up to John's death.

The boy had never seen a doctor until the day before he died on Nov. 29, 2013, Parker said.

The prosecutor urged jurors to ask themselves what they would do if they had a child with toes that were turning black and an all-over rash. He said they would urgently seek medical attention.

"They dithered; he withered," Parker said of the Clarks.

"They were playing with John's life. You would have taken John to the doctor."

Earlier in the day, the Clarks lawyers' urged jurors to put emotions aside as they determine their verdict.

"In our society, we try not to just act like an angry mob, grabbing our pitchforks and torches and heading off to the windmill to kill a monster," said John Phillips, Jennifer Clark's lawyer.

Jeromie Clark's lawyer, David Chow, told jurors they must steel themselves when looking at photographs of the dead child with tubes attached to his little body.

"It's easy to fall into the trap and place those pictures at the feet of those two people," he added, gesturing toward the Clarks in the prisoners dock.

Anny Sauvageau, Alberta's former chief medical examiner and now a consultant, reviewed John's files and determined he died from being given too much sodium and fluid in too short a time.

Sauvageau's testimony contradicted a forensic pathologist report by Elizabeth Brooks-Lim, the current chief medical examiner, that John was malnourished and died from sepsis.

Chow said for the jury to find the pair guilty of criminal negligence causing death, the Crown must prove beyond a reasonable doubt that their behaviour was a "marked and substantial departure in the standard of care expected of a reasonable person in the circumstances."

He said the Clarks may wish they had done something differently in hindsight, but they acted reasonably.

"No human being is subject to a standard of perfection," Chow said.

Both defence lawyers highlighted police photos of the Clarks' modest Calgary home that show healthy snacks, nutritional supplements, wellness books and baby gates.

"Just use your common sense: does this look like a home where the family is not properly looking out for the nutritional health of its children?" Chow asked. "No way."

The jury is to receive its instructions from Court of Queen's Bench Justice Paul Jeffrey on Thursday.

News from © The Canadian Press, 2018