He later claimed in the Court of Appeal that running her down was an accident and the jury should have been given the option of finding him guilty of manslaughter.
Robertson then tried the Supreme Court - making the same argument.
However, the Supreme Court ruled Robertson did not raise anything during the trial to suggest the alternative charge of manslaughter could have been reached.
The Herald has learned that Tony Douglas Robertson will appear before the Court of Appeal on February 3. Photo / Jason Oxenham
Robertson then applied to the Supreme Court to recall its decision, which would enable a fresh appeal.
That application has also been shot down.
"In dismissing the application for leave (in the first place), this Court's assessment was that nothing raised by the applicant suggested there was a credible narrative in the evidence for a manslaughter verdict," said the Supreme Court decision, released this afternoon.
"The application for recall is brought on the basis Mr Robertson's counsel on the leave application did not make submissions as to various evidential matters Mr Robertson says he was instructed to put forward.
"Mr Robertson wishes to argue these matters show there was a credible narrative for manslaughter."
However, the court ruled that those matters were already set out in "some detail" in the initial application.
"The application for recall accordingly in substance is an attempt to re-argue the application for leave," it said.
"Nothing has been advanced which would warrant a recall of our decision not to grant leave.
"The application for recall is accordingly dismissed."
His the crimes against the mother and grandmother came only months after Robertson was released from prison for similarly depraved offending.
Robertson was just 18 when he kidnapped and molested a 5-year-old girl in Tauranga in 2005.
He was jailed in October 2006 for eight years after being found guilty of seven charges, including indecently assaulting the girl and attempting to abduct two other children.
On his release in December 2013, he breached his conditions twice in a few weeks and was deemed such a danger that he was to be monitored strictly for a decade, the maximum period of an "Extended Supervision Order".
On May 24 2014 Robertson hit Gotingco while she was walking along a Birkdale street from a bus stop.
She had finished work and was on her way home.
Seeing her motionless body on the road, Robertson scooped her up, bundled her into the back of his BMW and took her to his nearby apartment just in time to make his curfew.
He was being monitored by Corrections via a GPS anklet at the time.
Once he was in the garage, beneath his home, the defendant sexually abused the injured woman before strangling her, stabbing her and slashing her throat.
Early the following morning, he wrapped Gotingco's body in a bed sheet and took her to Eskdale cemetery down the road where he dumped her body in thick bush.
