Shionah Carter lay dying after a brutal attack by her lover David Martin.
But an inquest was told that after a triple-0 call to police in which the pregnant Ms Carter could be heard moaning in the background, no officers were sent immediately and no ambulance called.
It was more than an hour before police arrived at her Beechboro home and another 20 minutes before paramedics were on the scene. By then, Ms Carter, 26, was dead.
For the attack in 2010, which a judge described as borne out of irrational jealousy and a five-day drug bender, Martin is serving 15 years in jail.
Deputy State Coroner Evelyn Vicker yesterday began investigating what role, if any, the delay by police may have had in Ms Carter's death.
At Martin's trial in 2011, the Supreme Court was told he flew into a rage after returning home from a night of partying to see two men he knew leaving his partner's unit.
Martin slapped and punched Ms Carter, threw a money box at her head, hit her with a piece of wood and ordered her to shower. As she lay on a bed, Martin sexually assaulted her.
Counsel assisting Kate Ellson told the court Sgt Andrew Bell took the initial triple-0 call at 3.21am on August 15, which could have come from Martin. The caller was evasive, giving a different name and refusing to give an address.
But police systems meant the address where the call came from was known immediately - but for "reasons unknown", Sgt Bell failed to act.
"In accordance with usual police procedures, the conduct of Sgt Bell was investigated and he was found to have neglected his duty and stood down from duty," Ms Ellson said.
Det-Sgt Craig Walsey, who conducted the police internal investigation, said Sgt Bell was "distraught" after he realised his inaction could have contributed to Ms Carter's death.
Sgt Bell has since retired from the police force.
Ms Carter's mother Kriss Derschow told the inquest her daughter was robust, calm, happy and compassionate. She said outside court she believed her daughter may still be alive if emergency services had arrived more promptly.