A man accused of killing a 15-month-old baby boy has told a jury he would have gone to prison for the boy's mother if she had told him she was responsible for his death.
Troy Taylor is on trial in the High Court in Christchurch accused of assaulting and murdering Ihaka Stokes at their home in 2015.
The 23-year-old was the partner of the boy's mother, Mikala Stokes.
Mr Taylor has alleged Ms Stokes, who was alone for several hours with the boy on the day in question, injured the baby.
Under cross examination today, Mr Taylor told the court he lied to the police when he said Ihaka must have had a fall in his cot that night, to protect Ms Stokes.
"I was so willing to protect Mikala, I was going to go to jail for her. I would have spent the rest of my life in prison if she came to me and said 'I did this'."
Ms Stokes told the court last week she had nothing to do with Ihaka's death.
Mr Taylor also rejected medical evidence given by a Crown witness suggesting the child died shortly after being injured.
Under cross-examination by Crown prosecutor Mark Zarifeh, Mr Taylor suggested it was the boy's mother, who was alone with Ihaka during the day, who injured the boy.
The baby died from head injuries several hours after Mr Taylor returned home.
Mr Zarifeh said a neuropathology professor who gave evidence last week believed Ihaka died shortly after being injured, and he had an exchange of views with Mr Taylor in court this afternoon.
"Mr Taylor, the thing that undoes your account is the independent medical evidence from Professor Smith."
"That's his opinion, he can get things wrong," Mr Taylor said. "Just because it's science, does that make it correct? Science gets lots of things wrong."