Brandon Lee Harris pleads guilty to the manslaughter of his son Kobe, who was aggressively shaken when just five weeks old

A young father already serving a jail sentence for shaking his five-week-old baby has now pleaded guilty to manslaughter after the little boy died of his injuries more than a year later.

A young father has pleaded guilty to manslaughter after shaking his five-week-old baby so hard the infant was left with terminal injuries.

Brandon Lee Harris, 23, was jailed for four years with a non-parole period of 18 months for the aggravated assault of baby boy Kobe in May 2018.

But after Kobe died from his injuries in August last year, Harris was rearrested in prison and further charged with manslaughter.

Harris initially told a triage nurse on the Yorke Peninsula that the baby was “breathing funny”.

The baby was taken to see a doctor who noted dilated pupils, irregular breathing and a bruise to the wrist.

The infant was admitted to Wallaroo Hospital where he was placed on emergency neonatal resuscitation and suffered seizures.

He was transferred to the Women’s and Children’s Hospital where doctors found swelling and bleeding on the brain consistent with the baby being shaken.

Kobe was left with critical injuries including brain damage, severe spastic quadriplegia, epilepsy and blindness.

Harris initially said the baby had thrown himself backwards during a feed and hit his head on the arm of a chair.

But he later admitted shaking the baby twice when he would not settle at night.

He also told police he had tried to force a bottle into the infant’s mouth, causing an injury to the tongue and lips.

Harris pleaded guilty to aggravated recklessly causing serious harm, and that court case was finalised while the baby was still alive.

In his initial sentencing in July last year, District Court Judge Rauf Soulio accepted that Harris was genuinely remorseful but concluded he had failed as a parent to protect his infant son.

“Given the baby’s age he was most vulnerable,” he said.

“As a father it was your duty to care and protect him from harm, not to cause him harm.”

Harris will face sentencing submissions in the Supreme Court in June.