The exact point where Ms Byrne's body was found in June 1995 has been a central issue in the proceedings, with prosecutors alleging she could only have landed so far out from the cliff face if she was hurled using a spear throw.

Burwood Local Court has previously been told that the place where the 24-year-old's body was discovered was wrongly identified by police during a video reconstruction in 1996.

Insp Jacob said it was not until 2004, after looking at photographs of the site, that he realised his mistake.

Defence Barrister Winston Terracini SC suggested there had been "a significant degree of incompetence" in the investigation up until that point.

"I don't agree with that at all," Insp Jacob said.

He also strongly denied suggestions that he had altered measurements relating to the position of the body to make them more consistent with Mr Byrne having been thrown.

"People make mistakes and a mistake was made in the use of the video for scientific purposes," he said.

The hearing continues.

Source News.com.au