The area where fire fighters lit a backburn which would ultimately destroy properties around Mt Wilson, Mt Tomah and neighbouring villages was never examined, despite the officer in charge specifically asking for it to be done, an inquiry has heard.
Detective Sergeant Laura Harvey told the coronial inquiry in Katoomba that she had asked fire investigators to check the scene on the corner of Mt Wilson Road and Bells Line of Road.
"As part of my investigation I made a request through the RFS fire investigator and NSW forensic service to conduct an examination of the scene where the backburn started," she said.
The fire, started in an attempt to stop the encroachment of the Gospers Mountain fire, quickly escaped, spotting across Mt Wilson Road to the east and spreading towards Berambing, Mt Tomah and other villages where homes were lost.
It eventually crossed the Grose River and became known as the Grose Valley fire.
When Sgt Harvey learnt that investigations had taken place not at the road intersection but at a lookout some distance away she contacted the RFS investigation team.
"I told [them] I wasn't happy about why they hadn't started at the point where I requested," Sgt Harvey said. "I wasn't really given an answer why in the end."
She said this meant that there had been no physical forensic investigation of the area where she believed the backburn spotted across the road.
"If a physical investigation had been undertaken would that have been useful for you," she was asked.
"Yes, I believe it needed to be done."
She believed it may have helped her determine the location of the spotovers.
One of the men who looked into the Grose Valley fire, RFS investigator Darin Howell, told the inquiry he had been told by an unnamed RFS person at the Katoomba fire centre that the Grose Valley fire was a continuation of the Gospers Mountain fire.
As a result, the investigators concentrated on an area of the Grose Valley which they viewed from Walls Lookout, more than two kilometres from the site where the backburn was lit.
Sgt Harvey, in her evidence, rejected other possible sources of the fire including power lines, lightning, campfires, smoking, equipment failures or juveniles misbehaving.