THE FAMILY of Dulcie Birt may find some comfort in knowing their loved one's killer will spend the next decade behind bars.
But the Ipswich woman's family are still no closer to knowing her final resting place.
While Alwyn Gwilliams admitted to unlawfully killing Ms Birt on or about October 21, 2009, his continuous lies meant the cause of Ms Birt's death remains unknown.
Gwilliams was sentenced on Friday after pleading guilty to manslaughter and interfering with a corpse.
Justice John Byrne stated, in his written judgment, Gwilliams, 44, was in a sexual relationship with Ms Birt and also maintained a de facto relationship with another woman.
On the night of October 21, 2009, Gwilliams and Ms Birt, 31, had a loud argument before going for a drive.
After initially dropping Ms Birt back to her Raceview home, where she lived with a boarder and her 16-year-old son, Gwilliams returned to pick up his phone charger.
Ms Bert got in the car with him again and has not been seen since.
Justice Byrne stated Gwilliams told his mother he crashed into a tree with Ms Birt in his car and Ms Birt "went forward, she came back, and she was quiet".
He told his mother he was scared and didn't want to tell police because they wouldn't believe him.
Justice Byrne outlined Gwilliams' chequered criminal history, including convictions for brutally assaulting former partners.
In his initial statement to police on October 25, 2009, Gwilliams claimed Ms Birt had asked him to stay at her house but he declined and had unsucessfully tried to contact her after.
Six weeks later in a sworn affidavit, Gwilliams claimed he crashed his car with Ms Birt in it, he tried to administer CPR unsuccessfully and then put her body in water at Jacob's Well, Woongoolba.
But police investigations found his utility did not have damage that would be expected from a fatal accident.
Justice Byrne found Gwilliams lied to avoid the truth, which would "reveal that he had assaulted Ms Bert and thereby killed her".
"Mr Gwilliams, I am persuaded, assaulted Ms Birt. But his lies and the concealment of the body mean that the nature of the assault remains unknown," he stated.
Justice Byrne said it was no credit to Gwilliams the he would not reveal Ms Bert's resting place.
He sentenced Gwilliams to 10 years jail.
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