She reiterated Maija's injuries could not have been caused by CPR, rolling from a bed, tumbling down steps, falling out of her stroller or being asphyxiated while co-sleeping with an adult, pointing to expect medical evidence that refuted any of these possibilities or a combination of them.
Gordon reminded the jury at the very minimum there were three fatal injuries to Maija's scalp, skull and across the surface of her brain.
"It would be nice if there is an accidental explanation for these injuries but there is not," she said.
Referring to an alleged fall from a bed, Gordon queried if this had in fact happened, would a good parent have left a child that age alone on one for up to two hours.
"You have to remember when she was returned to his care [by whanau members] she was well so you have to ask the important question, who inflicted these injuries?" Gordon urged the jury.
She reminded them it was Duff who had the sole care of Maija at the time she died.
"There is only one available conclusion - that it was the defendant who caused blows to her head by some form of assault, therefore at the very least he is guilty of Maija's manslaughter but the Crown says he is guilty of murder," she concluded.
Duff's lawyer Moana Dorset said there was no doubt Maija suffered blunt force trauma injuries which caused her death.
"That is what the experts tell us, but what they didn't tell us is how that was caused," she said.
She argued there were plenty of things Maija could have hit her head on.
She invited the jury to imagine what a father was going through following the death of his child, yet as soon as he could Duff had gone to the police station and immediately after Maija was declared dead agreed to an autopsy.
Dorset said the end result of expert witnesses' findings was Maija's death had been caused by blunt force trauma and they'd reached a scenario of how this might have happened, claiming this had been to bolster the Crown's case.
Pouring cold water on the prosecution's claim Duff had not immediately sought medical help for his daughter, Dorset reminded the jury once he found her unresponsive he attempted CPR and tried to suck mucus from around her nose, leaving the house in such a hurry he hadn't stopped to put shoes on.
"He held that baby in his arms, ran outside, carefully strapped his little dead baby into a vehicle, drove into Turangi, in a very short time he was at relatives hard out crying," Dorset said.
"This is not a trial by experts, this is a trial by jury, you are the finders of the facts . . . I don't need to remind you what a monstrous mistake it would be to find an innocent man guilty of murder," Dorset argued, saying not guilty of murder was their only possible verdict.
Summing up the trial, Justice Mathew Downs gave directions on the legal requirements needed to prove whether Duff was guilty of murder or manslaughter, telling jurors a murder charge includes one of manslaughter.
He emphasised they needed be sure Duff intended to cause Maija serious harm and that harm was likely to kill her.
He reiterated no one saw what happened to Maija, leaving the Crown to rely on expert evidence. Other evidence the jury heard was circumstantial. "But there is nothing second rate about circumstantial evidence," the judge said.
He directed the jury to take special care considering evidence Maija's parents used methamphetamine, this had only been called because traces of the drug had been found in the baby's system.
"There is no evidence he [Duff] used this in conjunction with her death or there was any involvement of it in the death of Maija," the judge emphasised.
