A judge has found a Calgary grandfather guilty of beating to death his five-year-old grandson — a boy who was sent to Canada from Mexico just months earlier by his mother who hoped he would have a better life.

Court of Queen's Bench Justice Richard Neufeld delivered his decision Wednesday morning, following Allan Perdomo Lopez's manslaughter trial, which took place in June.

Emilio Perdomo suffered a catastrophic brain injury on July 9, 2015.

It took Perdomo Lopez 2½ hours to get his unconscious grandson to a hospital after the child was injured. Emilio died eight days after he was admitted. The only people in the hospital room at the time were hospital staff.

The grandfather said Emilio suffered his fatal injury during an accidental fall down stairs days before the boy was brought to hospital.

But, in delivering his decision Wednesday morning, Court of Queen's Bench Richard Neufeld said Perdomo Lopez's statement to police was "not believable or reliable."

Neufeld took several factors into account in that finding that Emilio's fatal head injury was inflicted not accidental, including:

Evidence Emilio suffered months of physical abuse.

That the boy had multiple head injuries when he arrived at hospital.

Perdomo Lopez's lies to police.

Perdomo Lopez also waited hours after Emilio fell unconscious to take him to hospital, the judge noted.

"There is no rational explanation for withholding medical assistance if Emilio's injuries were accidental," said Neufeld.

Some of the Crown's strongest evidence came in the form of what it described as an apparent confession after police set up recording devices in Perdomo Lopez's car and home in the months after Emilio's death.

In one of the recorded conversations, Perdomo Lopez refers to Emilio as an "ungrateful demon" and says "I didn't want to kill that child."

Defence lawyer Darren Mahoney had argued Perdomo Lopez is a superstitious man who was actually praying for forgiveness for bringing Emilio from Mexico and bringing a curse into his house — not for killing the boy.

He also argued Emilio's injuries could have been inflicted by other adults who had access to the child.

The judge rejected those theories.

"He confessed to his God to having killed Emilio," said Neufeld. "The accused was asking God for forgiveness for what he did to his grandson."

Allan Perdomo, 59, was found guilty of manslaughter after his five-year-old grandson Emilio died of multiple blunt-force trauma injuries in 2015. (CBC)

Mahoney says he and his client are disappointed with the decision.

"There was a lot of evidence heard. We'll analyze the decision of the justice in light of the evidence that was let at trial and we'll make some decisions after meeting with the client about whether there is a reasonable prospect of appeal," he said.

Doctors testified during the trial that the boy's small body showed that he had suffered abuse for weeks if not months leading up to his death.

A man who worked at a local flea market every Sunday told the judge he watched as the boy deteriorated until he was barely able to walk and had a bandage on his head.

Perdomo Lopez's wife, Carolina Perdomo, was originally charged in the case but earlier this year her charge was stayed by prosecutor Shane Parker.

Five months before his death, Emilio's mother had sent her son from Mexico to live with Perdomo Lopez.

Based on photos taken of Emilio when he arrived in Calgary, the boy had no visible signs of injury.

But by the time he was taken to hospital, Emilio had bruises and scars in varying stages of healing.

The boy's back was marked with scars from being whipped with a belt, prosecutor Shane Parker told the court.

Bruises covered his feet, shins, knees, thighs, groin, stomach, chest, arms, face and head. And, on Emilio's left upper arm: a bruise in the shape of an adult-sized grip mark.