A sock and the remnants of a top removed from Katie Foreman's burned body the night she died both contained traces of the accelerant used to start the fire that killed her, a court has heard.
Police crime scene officer Detective Senior Constable Suzanne Sutherland spent more than 12 hours examining Ms Foreman's Corrimal home in the wake of the October 2011 fire that claimed the young solicitor's life.
Snr Const Sutherland yesterday told jurors in the trial of Ms Foreman's three alleged killers that an analysis of the sock, as well as fabric recovered from around Ms Foreman's wrists - believed to be cuffs from the top she had been wearing - returned a positive reading for petrol.
She said that discovery, along with the nature of the burns to Ms Foreman's body, led her to conclude Ms Foreman had been inside the bedroom of her Corrimal home when the fire was lit.
She later admitted during cross-examination that she could not say where in the room Ms Foreman may have been, or whether she may have been standing or sitting, or lying down (on the bed) at the time the fire ignited.
"You're of the opinion she was inside the bedroom at the time the petrol was applied?" Crown prosecutor Chris Maxwell, QC, asked.
"That's correct," Snr Const Sutherland replied.
"If it [petrol] was only on the sock, it may have been because she ran through it, but [petrol being on] other items of clothing suggests that it wasn't because she ran through a puddle or something.
Snr Const Sutherland said she believed Ms Foreman had not come in direct contact with the fire, and it was instead her clothes that had caught alight.
Ms Foreman's body was found by firefighters on the landing immediately outside the room.
Snr Const Sutherland also gave evidence about where she believed the petrol had been deposited into the room.
She named the bedhead, a bedside table and the north-eastern wall of the room as the areas of note based on the burn patterns she had observed.
However, the jury heard an accelerant detection dog did not identify the presence of any accelerant on the north-eastern wall, while samples taken from the area and later analysed also failed to locate any traces of petrol.
Snr Const Sutherland said she did not agree with the proposition that just because petrol wasn't found in that area, that meant it hadn't been there.
"The samples were taken the day after [the fire], a centimetre of water was covering [the area] when we arrived ... I believe each of those are factors why we got a negative result for accelerant," she said.
"I believe the damage done at [that site in the room] was because of ... the use of accelerant."
The trial continues.