Gordon Wood cop denies acting out of spite

The lead investigator in the Gordon Wood case has denied that a key expert abandoned impartiality as he looked into the death of Caroline Byrne, becoming a "de facto member of the NSW Police Force".

Detective Chief Inspector Paul Jacob also denied that he sought a retrial out of spite after Mr Wood was acquitted of Ms Byrne's murder in 2012.

Det Insp Jacob was questioned at length about his work with physicist Rod Cross in the Supreme Court on Tuesday, during Mr Wood's malicious prosecution case against the state of NSW.

"He wasn't beholden to us in any way," Det Insp Jacob said, adding that Associate Professor Cross was respectful and thorough.

Prof Cross gave evidence at Mr Wood's 2008 trial that Ms Byrne was "spear-thrown" to her death off a cliff at The Gap.

Mr Wood's barrister, Bruce McClintock SC, asked Det Insp Jacob why Prof Cross was sending him draft reports before they were finalised, and suggested the physicist had become a "de facto member of the NSW Police Force".

Det Insp Jacob rejected that but did say there was one thing he would do differently, when asked about his decision to seek Prof Cross' views on the topography of the area where Ms Byrne died.

Justice Elizabeth Fullerton asked why an assessment wasn't instead done by police photogrammetry experts and provided to Prof Cross, preserving the distinction between police and independent experts.

"On reflection, would you take a different approach?" she asked.

"Knowing what I'm being asked and issues that are being directed at me, absolutely," he said.

Mr McClintock asked Det Insp Jacob about an application he made for a retrial and put it to him that he was angry after Mr Wood's acquittal in 2012.

"I wasn't angry, I was certainly disappointed," Det Insp Jacob said.

Mr Mclintock then said: "You made this (retrial) application out of spite, didn't you?"

But the lead investigator denied that was the case, stating "Absolutely not."

Wood, a former personal assistant to stockbroker Rene Rivkin, was convicted of murdering Ms Byrne in 2008.

He served more than three years in jail before his acquittal.