A Newcastle man accused of murdering a baby says he lied for the child's mother who allegedly punched the six month old's face and body before shaking him vigorously, a jury has been told.
Jie William Smith 31, pleaded guilty to manslaughter of the baby early on February 9, 2019 in New Lambton, but the Crown has rejected this plea.
Crown prosecutor Neil Adams SC in his opening address on Monday in the Newcastle Supreme Court said Smith's neighbour was woken by a man standing at her doorway holding the child.
"Help me please. Something is wrong with the baby, he is not breathing, call an ambulance," Smith said, prompting the woman to dial triple zero.
Medical scans later found the baby suffered fractures to his skull, severe brain swelling, haemorrhages to the head and eyes, spinal chord trauma and extensive bruising to his legs, arms, head and neck.
Late the following evening his life support was switched off by his father.
The boy's mother was 26 and had five children when she and Smith rekindled an old friendship via Facebook and began dating in January 2019.
On the evening of February 8 the pair drove with the baby and another child around the Central Coast and Newcastle to score drugs, Mr Adams said.
They bought two points of ice and some cannabis, and returned to Smith's house in New Lambton.
The crown case is Smith murdered the child after the mother left on February 9 about 2.12am and before 4.20am when he began waking the neighbours.
Smith told police a few versions of a story that he dropped the baby who wriggled out of his arms while he was trying to settle or feed him.
Following his arrest, a listening device planted in his cell picked up a conversation in which he admits lying.
"The reason they charged me with murder I didn't speak, I didn't talk, but also .... I lied for her," he is recorded telling another inmate.
"I shouldn't have done that ... I was off me head, I had drugs in my system at the time ... but brother they are trying to ... make out like I am violent like I've done something to the baby.
"But the damage was already done by the mother before she left and took off."
Defence barrister Paul Rosser QC said this was when the mother's "cover-up story" began showing cracks.
About 2am the mother punched her son in the face twice and twice on his body, preceded by the words "why won't you stop crying," Mr Rosser said.
Smith was dividing up the drugs when he says he witnessed the jabs by the side of her hand, before "vigorously shaking the baby at least four times".
After he "remonstrated" with her she left with a child still asleep in her car, but the baby "was not right,' Mr Rosser said.
He said there was evidence the mother felt no attachment and had no interest in the baby and during the last week of his short life showed escalating tension due to his behaviour.
After feeling sick from the flu for days she texted her sister: "I can't even rest, (the baby) just cries and I'm very very very sick. I'm going to lose it soon."
He said the alleged injuries she caused could likely have preceded a seizure to explain why the child arched back and out of Smith's arms.
Detectives who attended the scene overheard Smith tell the woman over the phone "I am with you 100 per cent," which he says was in response to her telling him not to tell the police what she did to her baby.
Mr Rosser said the intended actions of the mother were compounded by the accidental dropping, and his client's plea to manslaughter acknowledges he should have sought urgent medical attention sooner.
