BRAMPTON, Ont. -- Heavy and repeated blows bruised a 10-year-old boy's head, blackened his eye, cracked his rib and caused widespread internal bleeding in the moments before his death, Ontario's top forensic pathologist testified Wednesday.

That "extensive blunt impact trauma" was the "primary fatal injury" in Shakeil Boothe's case, Dr. Michael Pollanen told a Toronto-area court.

The boy was already weakened by chronic injuries, malnutrition and infection in his lungs and blood, all of which contributed to his death, Pollanen said as he laid out the results of Shakeil's autopsy.

"This was a thin and poorly nourished boy," who weighed 60 pounds at the time of his death, the pathologist said.

Shakeil's body was covered in bruises, scrapes and scars, including several to the head, face, torso and limbs sustained "within minutes or hours of his death," Pollaned said.

He also said marks on the boy's shoulders suggested he had been frequently whipped or lashed, possibly with a belt.

"These are inflicted injuries," he said. "They're caused through the actions of another party on the body of this boy."

Shakeil was found dead in his bed on May 27, 2011, cold, stiff and foaming at the mouth. Prosecutors allege he had been abused and starved for months, kept chained to his bed except when he needed to use the bathroom or relatives were present.

His father Garfield Boothe and stepmother Nichelle Boothe-Rowe are both charged with second-degree murder.

Boothe-Rowe wiped her eyes with a tissue as photographs showing Shakeil's lifeless body were shown in court. The boy's father leaned forward, his head in his hands.

Photos showed scars of varying ages criss-crossing the boy's shoulders, back and legs; swelling in his hands and thighs; and open wounds on his shins that Pollanen described as "almost like a little crater."

Some lesions were yellowed with infection, the pathologist said.

Sometimes the body can fight off invading bacteria, but when a person's immune system is weakened -- through malnutrition or chronic injury, for example -- it may not be able to, he said.

"In the worst circumstances... those bacteria which are now in that wound can gain access to your bloodstream," a potentially fatal condition, he said.

It was only in examining the inside of Shakeil's body that Pollanen saw the extent of the boy's recent injuries, including "a carpet of bruising" on his chest, he testified.

These were likely caused by "punching, kicking (or) stomping," he said.

The autopsy also revealed brain damage from earlier head injuries and two previously fractured ribs that appeared to be healing, he said.

It wasn't possible, however, to say exactly when Shakeil had died, Pollanen said, noting the level of infection in the boy's body may have sped up the decomposition process.

The paramedics who found the 10-year-old's body have testified they believe he had been dead for some time.

   The Crown alleges Boothe and Boothe-Rowe discovered the death on May 26, but held off calling authorities for a day while they tried to cover their tracks.