Tamehana Huata was a gentle, loving stepfather, not a "monster" who killed his stepson, the High Court heard yesterday.
The defence opened its case for a man charged with killing two-year-old Matiu Wereta at his Flaxmere home in October 2015.
Huata is charged with the manslaughter and injuring with intent to injure Matiu. Huata was 17 at time of the boy's death.
The essence of the Crown's evidence presented to the jury last week was that the serious head injuries, which led to the death of Matiu, were caused by multiple blows to the head, not by him falling into a brick wall as claimed by the defence.
In his opening, Huata's defence lawyer Russell Fairbrother told the jury that nothing is as black and white as it seems in the real world and quoted fictional private detective Sherlock Holmes.
"There's nothing more deceptive than an obvious fact."
Several expert witnesses were called yesterday, one being forensic odontologist Alexander Stewart Forrest of an Australian university, who said he had provided comment and advice on more than 50 bite-mark cases throughout his career.
Dr Forrest said after viewing photographs of the alleged bite marks on Matiu's body he would not have taken the matter further; concluding they did not meet enough class characteristics for a human-inflicted bite mark.
He said it's possible other injuries may resemble bite marks, those including being hit with a circular belt buckle, coming into contact with a domestic iron and forceful contact with the heel of a shoe.
Matiu's puncture wounds were not typical of bite marks, Dr Forrest said.
Crown prosecutor Steve Manning said Dr Forrest could not rule out the potential that the marks may be bite marks.
The Crown had already provided numerous expert medical witnesses who said the severity of Matiu's head injuries were more akin to those of a major car crash victim.
However, the defence told the jury Matiu's injuries were caused by a hyperactive child who catapulted into a small brick wall after accidentally tripping on a towel.
Mr Fairbrother asked the jury to reflect on Huata's grief following the incident, asking them to question why a man who had a loving relationship with the boy would have turned into a monster.
"The real question you're being asked to decide is why would a person of this background and decent attributes suddenly become a, sort of, monster," Mr Fairbrother said.
The trial is expected to finish at the end of this week.