The Crown has accused a man of lying to police and his family when he claimed a five-month-old baby drowned in his care.
Troy Louis Stuart Solomon, 25, has denied murdering the girl at the trial which began today in the High Court in Auckland.
The girl's name and relationship to Mr Solomon has been suppressed.
Crown prosecutor Aaron Perkins told the jury Mr Solomon subjected the baby to a violent assault that left her with catastrophic head injuries, but Mr Solomon has said she drowned in the bath.
Mr Perkins said Mr Solomon was looking after her at his Pukekohe house while his partner was out supermarket shopping in July 2014.
He said shortly before midday he called 111 and paramedics arrived not long afterwards but could not save her.
Mr Perkins said Mr Solomon repeated the drowning story to police, his family and his partner's family.
However after a police interview that lasted hours, Mr Solomon changed his story.
The change only came after detectives confronted him with evidence from a pathologist that showed the baby had severe head injuries and a broken leg, Mr Perkins said.
Mr Solomon then told police that he had been smoking marijuana that morning and had been bathing the baby and she slipped from his grip, landing on the floor, he said
Mr Perkins described that explanation as nonsense.
In answer to police questions about why he had not told the truth, Mr Solomon said he did not think his partner's family would believe him and he was scared, Mr Perkins said.
The Crown will call 28 witnesses, including paediatric brain experts who would show that Mr Solomon's explanations could not be true, Mr Perkins said.
The evidence showed that the baby died soon after being injured and the fracture to the leg suggested she could have been swung by the leg into a hard surface, he said.
The Crown prosecutor said there was also evidence that showed an earlier leg fracture.
The trial is set down for three weeks.
