A 29-year-old man is on trial in the WA Supreme Court accused of murdering his baby son, who died almost a year after suffering "head to foot" injuries that included bleeding on the brain, broken ribs and bruising all over his body.
WARNING: This story contains content that some people may find distressing.
Micheal Ashley Macrae is alleged to have inflicted the injuries on his seven-week-old son Nathaniel, either through violent behaviour, or by "vigorously and excessively" shaking him at a home in the Wheatbelt town of Narrogin in October 2017.
The court was told Mr Macrae was no longer in a relationship with the child's mother, Erica Lawrence, but she had asked him to look after Nathaniel so she could go to the town's hospital for treatment for her back.
State prosecutor James Mactaggart, said not long after Mr Macrae had picked up the child, Ms Lawrence, who was Nathaniel's primary carer, changed her mind and asked for him to be brought back to her.
Mr Macrae repeatedly refused to return the child, saying he wanted to spend time with his son.
About 36 hours later the child was rushed to hospital, where staff formed the view he had suffered severe brain injuries that were "consistent with abusive head trauma".
Mr Mactaggart said the child also had bruising to his face, chest abdomen and buttocks, as well as injuries to his arms, spine and fractured ribs.
"The state's case is that in the early hours of the morning on October 9, 2017 or late in the evening of October 8, 2017, the accused mistreated Nathaniel by either shaking him or subjecting him to some other violent behaviour, causing the injuries," Mr Mactaggart said.
Nathaniel died just after his first birthday
The court was told Nathaniel was left with no brain function, incapable of any movement and needing 24-hour care.
Medical experts estimated he would have a life expectancy of 20 years at the most, but he died at his mother's home in September 2018, just after his first birthday.
Mr Mactaggart said the cause of his death was pneumonia in combination with an acquired brain injury.
Mr Macrae conducted a three-hour recorded interview with police, in which the court heard he denied anything happened while he was caring for his son.
He also claimed he was "being set up" by Nathaniel's mother, suggesting the child had already suffered the injuries by the time he picked him up.
But Mr Mactaggart said that was not possible because about seven hours after Mr Macrae took his son, police had conducted a welfare check on him and found nothing untoward.
Mr Macrae denies murdering his son, with his lawyer Edward Fitzpatrick telling the court his client did not injure Nathaniel and he does not know who did.
Roommate says child was 'limp' after he heard loud thud
Nathan Kalling was in his bedroom in the house at the time Nathaniel was alleged to have suffered the injuries.
He testified that the baby had been unsettled and he heard Mr Macrae say in a stressed and frustrated tone something like: 'I should just drop you back to your mother's".
He said he fell asleep but woke up to the sound of a thud, telling the court: "It sounded like a thud on the door or something fell over".
"I'm a deep sleeper. It was loud enough to wake me and my dog up."
Mr Kalling said he went back to sleep but was woken up in the morning by Mr Macrae coming into his room holding Nathaniel saying "my boy, my boy".
He told the court the child appeared limp and was gasping for air.
Mr Kalling said he told Mr Macrae to call triple zero before he grabbed the baby, who was wearing a dirty nappy.
He said Mr Macrae was not making much sense on the phone so he grabbed it and did what the operator told him to do.
But he testified he hung up the phone when he was told the nearest ambulance was in another town about half an hour away.
The court has heard Mr Macrae then took the child to the town's hospital himself.
