A man who spent more than four years denying that he killed his pregnant girlfriend took police on a wild goose chase to Central Coast bushland where he claimed he had buried her body.

Paul James Wilkinson, a former Aboriginal liaison officer with the NSW Police, pleaded guilty in the Supreme Court last month to murdering Kylie Labouchardiere, 23.

The student nurse was last seen alive at Sutherland, in Sydney's south, on April 28, 2004.

Wilkinson has also pleaded guilty to setting fire to his rented home in Picnic Point.

Police have been unable to find Ms Labouchardiere's remains, despite admissions by Wilkinson that he strangled her and dumped her body in dense bushland, a court has heard.

For the first time the Herald can reveal that Wilkinson told police he strangled Ms Labouchardiere on or near the Mooney Mooney Bridge and later buried her body on a fire trail about 700 metres off the Old Pacific Highway.

The information had been suppressed by the Supreme Court to protect the integrity of the police search.

On October 13, Wilkinson provided police with a rough map of the area but they were unable to find the remains when they searched the area two days later.

The court heard he then agreed to go to the site with police to pinpoint the location where he had buried the body.

However after three days of scouring the dense scrub and bushland with cadaver dogs, anthropologists and other experts, police said there was "no chance" of finding a body in that area.

Wilkinson had previously pinned the murder on a police officer but in October he pleaded guilty to the manslaughter of Ms Labouchardiere, claiming it was on the grounds of provocation and/or substantial mental impairment.

On November 12, after admitting he had murdered Ms Labouchardiere, Wilkinson continued to insist he could help locate the body and police brought in a laptop with video of the area, hoping he could do so.

However further searches have failed.

In court for sentencing submissions yesterday Wilkinson sat motionless in the dock with his head down, refusing to look at anyone in the public gallery.

The matter was adjourned until later this month after Wilkinson's barrister, Terry Healey, told the court his client had provided new information that police needed to verify by checking phone records.

Ms Labouchardiere's family have waited more than four years to be able to bury her body.

Only Wilkinson can control how much longer they will wait.